diff --git a/.travis.yml b/.travis.yml
index 5e55165..1e8e3a0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,4 +16,4 @@ branches:
 before_install: gem install bundler
 bundler_args: "--deployment --without development --jobs=3 --retry=3"
 
-script: "./script/ci/travis.sh"
+script: bundle exec rake --trace
diff --git a/Gemfile b/Gemfile
index 862f93f..c9d145e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -42,6 +42,7 @@ group :test do
   gem "fixture_builder",           "~> 0.4.1"
   gem "factory_girl_rails",        "~> 4.5.0"
   gem "rspec-collection_matchers", "~> 1.1.2"
+  gem "webmock",                   "~> 1.21.0"
 end
 
 group :development, :test do
diff --git a/Gemfile.lock b/Gemfile.lock
index ffd57ed..d1f992c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,7 +2,11 @@ PATH
   remote: .
   specs:
     diaspora_federation (0.0.3)
+      faraday (~> 0.9.0)
+      faraday_middleware (~> 0.9.0)
       nokogiri (~> 1.6, >= 1.6.6)
+      typhoeus (~> 0.7.0)
+      valid (~> 0.5.0)
     diaspora_federation-rails (0.0.3)
       diaspora_federation (= 0.0.3)
       rails (~> 4.2)
@@ -45,6 +49,7 @@ GEM
       minitest (~> 5.1)
       thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
+    addressable (2.3.8)
     arel (6.0.0)
     ast (2.0.0)
     astrolabe (1.3.0)
@@ -56,14 +61,22 @@ GEM
       simplecov (>= 0.7.1, < 1.0.0)
     coderay (1.1.0)
     columnize (0.9.0)
+    crack (0.4.2)
+      safe_yaml (~> 1.0.0)
     diff-lcs (1.2.5)
     docile (1.1.5)
     erubis (2.7.0)
+    ethon (0.7.4)
+      ffi (>= 1.3.0)
     factory_girl (4.5.0)
       activesupport (>= 3.0.0)
     factory_girl_rails (4.5.0)
       factory_girl (~> 4.5.0)
       railties (>= 3.0.0)
+    faraday (0.9.1)
+      multipart-post (>= 1.2, < 3)
+    faraday_middleware (0.9.2)
+      faraday (>= 0.7.4, < 0.10)
     ffi (1.9.10)
     fixture_builder (0.4.1)
       activerecord (>= 2)
@@ -111,6 +124,7 @@ GEM
     mini_portile (0.6.2)
     minitest (5.7.0)
     multi_json (1.11.1)
+    multipart-post (2.0.0)
     nenv (0.2.0)
     nokogiri (1.6.6.2)
       mini_portile (~> 0.6.0)
@@ -193,6 +207,7 @@ GEM
       rainbow (>= 1.99.1, < 3.0)
       ruby-progressbar (~> 1.4)
     ruby-progressbar (1.7.5)
+    safe_yaml (1.0.4)
     shellany (0.0.1)
     simplecov (0.10.0)
       docile (~> 1.1.0)
@@ -218,10 +233,16 @@ GEM
     systemu (2.6.5)
     thor (0.19.1)
     thread_safe (0.3.5)
+    typhoeus (0.7.2)
+      ethon (>= 0.7.4)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
     uuid (2.3.8)
       macaddr (~> 1.0)
+    valid (0.5.0)
+    webmock (1.21.0)
+      addressable (>= 2.3.6)
+      crack (>= 0.3.2)
     yard (0.8.7.6)
 
 PLATFORMS
@@ -250,6 +271,7 @@ DEPENDENCIES
   spring-watcher-listen
   sqlite3 (~> 1.3.10)
   uuid (~> 2.3.8)
+  webmock (~> 1.21.0)
   yard
 
 BUNDLED WITH
diff --git a/README.md b/README.md
index a7818ed..73b5f5b 100644
--- a/README.md
+++ b/README.md
@@ -43,10 +43,10 @@ DiasporaFederation.configure do |config|
   config.server_uri = AppConfig.pod_uri
 
   config.define_callbacks do
-    on :person_webfinger_fetch do |handle|
-      person = Person.find_local_by_diaspora_handle(handle)
+    on :person_webfinger_fetch do |diaspora_id|
+      person = Person.find_local_by_diaspora_id(diaspora_id)
       if person
-        DiasporaFederation::WebFinger::WebFinger.new(
+        DiasporaFederation::Discovery::WebFinger.new(
           # ...
         )
       end
diff --git a/app/controllers/diaspora_federation/h_card_controller.rb b/app/controllers/diaspora_federation/h_card_controller.rb
index 70e8821..65e700d 100644
--- a/app/controllers/diaspora_federation/h_card_controller.rb
+++ b/app/controllers/diaspora_federation/h_card_controller.rb
@@ -9,10 +9,12 @@ module DiasporaFederation
     def hcard
       person_hcard = DiasporaFederation.callbacks.trigger(:person_hcard_fetch, params[:guid])
 
-      return render nothing: true, status: 404 if person_hcard.nil?
-
-      logger.info "hcard profile request for: #{person_hcard.nickname}:#{person_hcard.guid}"
-      render html: person_hcard.to_html.html_safe
+      if person_hcard.nil?
+        render nothing: true, status: 404 if person_hcard.nil?
+      else
+        logger.info "hcard profile request for: #{person_hcard.nickname}:#{person_hcard.guid}"
+        render html: person_hcard.to_html.html_safe
+      end
     end
   end
 end
diff --git a/app/controllers/diaspora_federation/webfinger_controller.rb b/app/controllers/diaspora_federation/webfinger_controller.rb
index 3343e1c..ac9fd5a 100644
--- a/app/controllers/diaspora_federation/webfinger_controller.rb
+++ b/app/controllers/diaspora_federation/webfinger_controller.rb
@@ -37,10 +37,12 @@ module DiasporaFederation
     def legacy_webfinger
       person_wf = find_person_webfinger(params[:q]) if params[:q]
 
-      return render nothing: true, status: 404 if person_wf.nil?
-
-      logger.info "webfinger profile request for: #{person_wf.acct_uri}"
-      render body: person_wf.to_xml, content_type: "application/xrd+xml"
+      if person_wf.nil?
+        render nothing: true, status: 404
+      else
+        logger.info "webfinger profile request for: #{person_wf.acct_uri}"
+        render body: person_wf.to_xml, content_type: "application/xrd+xml"
+      end
     end
 
     private
@@ -48,11 +50,11 @@ module DiasporaFederation
     # creates the host-meta xml with the configured server_uri and caches it
     # @return [String] XML string
     def self.host_meta_xml
-      @host_meta_xml ||= WebFinger::HostMeta.from_base_url(DiasporaFederation.server_uri.to_s).to_xml
+      @host_meta_xml ||= Discovery::HostMeta.from_base_url(DiasporaFederation.server_uri.to_s).to_xml
     end
 
     def find_person_webfinger(query)
-      DiasporaFederation.callbacks.trigger(:person_webfinger_fetch, query.strip.downcase.gsub("acct:", ""))
+      DiasporaFederation.callbacks.trigger(:person_webfinger_fetch, query.strip.downcase.sub("acct:", ""))
     end
   end
 end
diff --git a/diaspora_federation.gemspec b/diaspora_federation.gemspec
index 77d9274..6e58eae 100644
--- a/diaspora_federation.gemspec
+++ b/diaspora_federation.gemspec
@@ -21,4 +21,8 @@ Gem::Specification.new do |s|
   s.required_ruby_version = "~> 2.0"
 
   s.add_dependency "nokogiri", "~> 1.6", ">= 1.6.6"
+  s.add_dependency "faraday", "~> 0.9.0"
+  s.add_dependency "faraday_middleware", "~> 0.9.0"
+  s.add_dependency "typhoeus", "~> 0.7.0"
+  s.add_dependency "valid", "~> 0.5.0"
 end
diff --git a/lib/diaspora_federation.rb b/lib/diaspora_federation.rb
index 1580b65..ebbb1ef 100644
--- a/lib/diaspora_federation.rb
+++ b/lib/diaspora_federation.rb
@@ -3,8 +3,13 @@ require "diaspora_federation/logging"
 require "diaspora_federation/callbacks"
 require "diaspora_federation/properties_dsl"
 require "diaspora_federation/entity"
+require "diaspora_federation/validators"
 
-require "diaspora_federation/web_finger"
+require "diaspora_federation/fetcher"
+
+require "diaspora_federation/entities"
+
+require "diaspora_federation/discovery"
 
 # diaspora* federation library
 module DiasporaFederation
@@ -30,6 +35,12 @@ module DiasporaFederation
     #   config.server_uri = AppConfig.pod_uri
     attr_accessor :server_uri
 
+    # Set the bundle of certificate authorities (CA) certificates
+    #
+    # @example
+    #   config.certificate_authorities = AppConfig.environment.certificate_authorities.get
+    attr_accessor :certificate_authorities
+
     # configure the federation library
     #
     # @example
@@ -63,10 +74,17 @@ module DiasporaFederation
     # called from after_initialize
     # @raise [ConfigurationError] if the configuration is incomplete or invalid
     def validate_config
-      configuration_error "Missing server_uri" unless @server_uri.respond_to? :host
+      configuration_error "server_uri: Missing or invalid" unless @server_uri.respond_to? :host
+
+      configuration_error "certificate_authorities: Not configured" if @certificate_authorities.nil?
+      unless File.file? @certificate_authorities
+        configuration_error "certificate_authorities: File not found: #{@certificate_authorities}"
+      end
+
       unless @callbacks.definition_complete?
         configuration_error "Missing handlers for #{@callbacks.missing_handlers.join(', ')}"
       end
+
       logger.info "successfully configured the federation library"
     end
 
diff --git a/lib/diaspora_federation/discovery.rb b/lib/diaspora_federation/discovery.rb
new file mode 100644
index 0000000..95cd7e9
--- /dev/null
+++ b/lib/diaspora_federation/discovery.rb
@@ -0,0 +1,14 @@
+module DiasporaFederation
+  # This module provides the namespace for the various classes implementing
+  # WebFinger and other protocols used for metadata discovery on remote servers
+  # in the Diaspora* network.
+  module Discovery
+  end
+end
+
+require "diaspora_federation/discovery/exceptions"
+require "diaspora_federation/discovery/xrd_document"
+require "diaspora_federation/discovery/host_meta"
+require "diaspora_federation/discovery/web_finger"
+require "diaspora_federation/discovery/h_card"
+require "diaspora_federation/discovery/discovery"
diff --git a/lib/diaspora_federation/discovery/discovery.rb b/lib/diaspora_federation/discovery/discovery.rb
new file mode 100644
index 0000000..5ecb1d6
--- /dev/null
+++ b/lib/diaspora_federation/discovery/discovery.rb
@@ -0,0 +1,91 @@
+module DiasporaFederation
+  module Discovery
+    # This class contains the logic to fetch all data for the given diaspora ID
+    class Discovery
+      include DiasporaFederation::Logging
+
+      # @return [String] the diaspora ID of the account
+      attr_reader :diaspora_id
+
+      # @param [String] diaspora_id the diaspora id to discover
+      def initialize(diaspora_id)
+        @diaspora_id = clean_diaspora_id(diaspora_id)
+      end
+
+      # fetch all metadata for the account
+      # @return [Person]
+      def fetch
+        logger.info "Fetch data for #{diaspora_id}"
+
+        unless diaspora_id == clean_diaspora_id(webfinger.acct_uri)
+          raise DiscoveryError, "Diaspora ID does not match: Wanted #{diaspora_id} but got" \
+                                " #{clean_diaspora_id(webfinger.acct_uri)}"
+        end
+
+        person
+      end
+
+      private
+
+      def clean_diaspora_id(diaspora_id)
+        diaspora_id.strip.sub("acct:", "").to_s.downcase
+      end
+
+      def get(url, http_fallback=false)
+        logger.info "Fetching #{url} for #{diaspora_id}"
+        response = Fetcher.get(url)
+        raise "Failed to fetch #{url}: #{response.status}" unless response.success?
+        response.body
+      rescue => e
+        if http_fallback && url.start_with?("https://")
+          logger.warn "Retry with http: #{url} for #{diaspora_id}: #{e.class}: #{e.message}"
+          url.sub!("https://", "http://")
+          retry
+        else
+          raise DiscoveryError, "Failed to fetch #{url} for #{diaspora_id}: #{e.class}: #{e.message}"
+        end
+      end
+
+      def host_meta_url
+        domain = diaspora_id.split("@")[1]
+        "https://#{domain}/.well-known/host-meta"
+      end
+
+      def legacy_webfinger_url_from_host_meta
+        # this tries the xrd url with https first, then falls back to http
+        host_meta = HostMeta.from_xml get(host_meta_url, true)
+        host_meta.webfinger_template_url.gsub("{uri}", "acct:#{diaspora_id}")
+      end
+
+      def webfinger
+        @webfinger ||= WebFinger.from_xml get(legacy_webfinger_url_from_host_meta)
+      end
+
+      def hcard
+        @hcard ||= HCard.from_html get(webfinger.hcard_url)
+      end
+
+      def person
+        Entities::Person.new(
+          guid:         hcard.guid || webfinger.guid,
+          diaspora_id:  diaspora_id,
+          url:          webfinger.seed_url,
+          exported_key: hcard.public_key || webfinger.public_key,
+          profile:      profile
+        )
+      end
+
+      def profile
+        Entities::Profile.new(
+          diaspora_id:      diaspora_id,
+          first_name:       hcard.first_name,
+          last_name:        hcard.last_name,
+          image_url:        hcard.photo_large_url,
+          image_url_medium: hcard.photo_medium_url,
+          image_url_small:  hcard.photo_small_url,
+          searchable:       hcard.searchable
+        )
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/web_finger/exceptions.rb b/lib/diaspora_federation/discovery/exceptions.rb
similarity index 79%
rename from lib/diaspora_federation/web_finger/exceptions.rb
rename to lib/diaspora_federation/discovery/exceptions.rb
index 5883dc7..38c536a 100644
--- a/lib/diaspora_federation/web_finger/exceptions.rb
+++ b/lib/diaspora_federation/discovery/exceptions.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  module WebFinger
+  module Discovery
     # Raised, if the XML structure is invalid
     class InvalidDocument < RuntimeError
     end
@@ -11,5 +11,9 @@ module DiasporaFederation
     # * if the html passed to {HCard.from_html} in some way is malformed, invalid or incomplete.
     class InvalidData < RuntimeError
     end
+
+    # Raised, if there is an error while discover a new person
+    class DiscoveryError < RuntimeError
+    end
   end
 end
diff --git a/lib/diaspora_federation/web_finger/h_card.rb b/lib/diaspora_federation/discovery/h_card.rb
similarity index 88%
rename from lib/diaspora_federation/web_finger/h_card.rb
rename to lib/diaspora_federation/discovery/h_card.rb
index 76025e9..e9222f5 100644
--- a/lib/diaspora_federation/web_finger/h_card.rb
+++ b/lib/diaspora_federation/discovery/h_card.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  module WebFinger
+  module Discovery
     # This class provides the means of generating an parsing account data to and
     # from the hCard format.
     # hCard is based on +RFC 2426+ (vCard) which got superseded by +RFC 6350+.
@@ -15,17 +15,17 @@ module DiasporaFederation
     #
     # @example Creating a hCard document from a person hash
     #   hc = HCard.new(
-    #     guid:                  "0123456789abcdef",
-    #     nickname:              "user",
-    #     full_name:             "User Name",
-    #     seed_url:              "https://server.example/",
-    #     photo_large_url:       "https://server.example/uploads/l.jpg",
-    #     photo_medium_url:      "https://server.example/uploads/m.jpg",
-    #     photo_small_url:       "https://server.example/uploads/s.jpg",
-    #     serialized_public_key: "-----BEGIN PUBLIC KEY-----\nABCDEF==\n-----END PUBLIC KEY-----",
-    #     searchable:            true,
-    #     first_name:            "User",
-    #     last_name:             "Name"
+    #     guid:             "0123456789abcdef",
+    #     nickname:         "user",
+    #     full_name:        "User Name",
+    #     seed_url:         "https://server.example/",
+    #     photo_large_url:  "https://server.example/uploads/l.jpg",
+    #     photo_medium_url: "https://server.example/uploads/m.jpg",
+    #     photo_small_url:  "https://server.example/uploads/s.jpg",
+    #     public_key:       "-----BEGIN PUBLIC KEY-----\nABCDEF==\n-----END PUBLIC KEY-----",
+    #     searchable:       true,
+    #     first_name:       "User",
+    #     last_name:        "Name"
     #   )
     #   html_string = hc.to_html
     #
@@ -48,12 +48,12 @@ module DiasporaFederation
       property :guid
 
       # @!attribute [r] nickname
-      #   the first part of the diaspora handle
+      #   the first part of the diaspora ID
       #   @return [String] nickname
       property :nickname
 
       # @!attribute [r] full_name
-      #  @return [String] display name of the user
+      #   @return [String] display name of the user
       property :full_name
 
       # @!attribute [r] url
@@ -70,10 +70,8 @@ module DiasporaFederation
       #   DER-encoded PKCS#1 key beginning with the text
       #   "-----BEGIN PUBLIC KEY-----" and ending with "-----END PUBLIC KEY-----".
       #
-      #   @note the public key is new in the hcard and is optional now.
-      #
       #   @return [String] public key
-      property :public_key, default: nil
+      property :public_key
 
       # @!attribute [r] photo_large_url
       #   @return [String] url to the big avatar (300x300)
@@ -163,8 +161,8 @@ module DiasporaFederation
       def self.from_html(html_string)
         doc = parse_html_and_validate(html_string)
 
-        data = {
-          guid:             content_from_doc(doc, :uid),
+        new(
+          guid:             guid_from_doc(doc),
           nickname:         content_from_doc(doc, :nickname),
           full_name:        content_from_doc(doc, :fn),
           url:              element_from_doc(doc, :url)["href"],
@@ -172,15 +170,13 @@ module DiasporaFederation
           photo_medium_url: photo_from_doc(doc, :photo_medium),
           photo_small_url:  photo_from_doc(doc, :photo_small),
           searchable:       (content_from_doc(doc, :searchable) == "true"),
+          # TODO: public key is new and can be missing
+          public_key:       (content_from_doc(doc, :key) unless element_from_doc(doc, :key).nil?),
 
-          # TODO: change me!  ###################
+          # TODO: remove first_name and last_name!
           first_name:       content_from_doc(doc, :given_name),
           last_name:        content_from_doc(doc, :family_name)
-          #######################################
-        }
-        # TODO: public key is new and can be missing
-        data[:public_key] = content_from_doc(doc, :key) unless element_from_doc(doc, :key).nil?
-        new(data)
+        )
       end
 
       private
@@ -288,6 +284,14 @@ module DiasporaFederation
         element_from_doc(doc, photo_selector)["src"]
       end
       private_class_method :photo_from_doc
+
+      # @deprecated hack for old hcard
+      # @todo remove this when all pods have the new generator
+      def self.guid_from_doc(doc)
+        uid_element = element_from_doc(doc, :uid)
+        uid_element.content unless uid_element[:class].include? "nickname"
+      end
+      private_class_method :guid_from_doc
     end
   end
 end
diff --git a/lib/diaspora_federation/web_finger/host_meta.rb b/lib/diaspora_federation/discovery/host_meta.rb
similarity index 86%
rename from lib/diaspora_federation/web_finger/host_meta.rb
rename to lib/diaspora_federation/discovery/host_meta.rb
index 444c16f..9346b6e 100644
--- a/lib/diaspora_federation/web_finger/host_meta.rb
+++ b/lib/diaspora_federation/discovery/host_meta.rb
@@ -1,6 +1,6 @@
 
 module DiasporaFederation
-  module WebFinger
+  module Discovery
     # Generates and parses Host Meta documents.
     #
     # This is a minimal implementation of the standard, only to the degree of what
@@ -19,8 +19,13 @@ module DiasporaFederation
     class HostMeta
       private_class_method :new
 
+      # @param [String] webfinger_url the webfinger-url
+      def initialize(webfinger_url)
+        @webfinger_url = webfinger_url
+      end
+
       # URL fragment to append to the base URL
-      WEBFINGER_SUFFIX = "webfinger?q={uri}"
+      WEBFINGER_SUFFIX = "/webfinger?q={uri}"
 
       # Returns the WebFinger URL that was used to build this instance (either from
       # xml or by giving a base URL).
@@ -42,18 +47,14 @@ module DiasporaFederation
 
       # Builds a new HostMeta instance and constructs the WebFinger URL from the
       # given base URL by appending HostMeta::WEBFINGER_SUFFIX.
+      # @param [String, URL] base_url the base-url for the webfinger-url
       # @return [HostMeta]
       # @raise [InvalidData] if the webfinger url is malformed
       def self.from_base_url(base_url)
-        raise ArgumentError, "base_url is not a String" unless base_url.instance_of?(String)
-
-        base_url += "/" unless base_url.end_with?("/")
-        webfinger_url = base_url + WEBFINGER_SUFFIX
+        webfinger_url = "#{base_url.to_s.chomp('/')}#{WEBFINGER_SUFFIX}"
         raise InvalidData, "invalid webfinger url: #{webfinger_url}" unless webfinger_url_valid?(webfinger_url)
 
-        hm = allocate
-        hm.instance_variable_set(:@webfinger_url, webfinger_url)
-        hm
+        new(webfinger_url)
       end
 
       # Reads the given Host Meta XML document string and populates the
@@ -67,16 +68,14 @@ module DiasporaFederation
         webfinger_url = webfinger_url_from_xrd(data)
         raise InvalidData, "invalid webfinger url: #{webfinger_url}" unless webfinger_url_valid?(webfinger_url)
 
-        hm = allocate
-        hm.instance_variable_set(:@webfinger_url, webfinger_url)
-        hm
+        new(webfinger_url)
       end
 
       # Applies some basic sanity-checking to the given URL
       # @param [String] url validation subject
       # @return [Boolean] validation result
       def self.webfinger_url_valid?(url)
-        !url.nil? && url.instance_of?(String) && url =~ %r{^https?:\/\/.*\{uri\}}i
+        !url.nil? && url.instance_of?(String) && url =~ %r{^https?:\/\/.*\/.*\{uri\}.*}i
       end
       private_class_method :webfinger_url_valid?
 
diff --git a/lib/diaspora_federation/web_finger/web_finger.rb b/lib/diaspora_federation/discovery/web_finger.rb
similarity index 86%
rename from lib/diaspora_federation/web_finger/web_finger.rb
rename to lib/diaspora_federation/discovery/web_finger.rb
index a0ddc7a..d8759a8 100644
--- a/lib/diaspora_federation/web_finger/web_finger.rb
+++ b/lib/diaspora_federation/discovery/web_finger.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  module WebFinger
+  module Discovery
     # The WebFinger document used for Diaspora* user discovery is based on an older
     # draft of the specification you can find in the wiki of the "webfinger" project
     # on {http://code.google.com/p/webfinger/wiki/WebFingerProtocol Google Code}
@@ -147,20 +147,23 @@ module DiasporaFederation
       def self.from_xml(webfinger_xml)
         data = parse_xml_and_validate(webfinger_xml)
 
-        hcard_url, seed_url, guid, profile_url, atom_url, salmon_url, public_key = parse_links(data)
+        links = data[:links]
+
+        # TODO: remove! public key is deprecated in webfinger
+        public_key  = parse_link(links, REL_PUBKEY)
 
         new(
           acct_uri:    data[:subject],
           alias_url:   data[:aliases].first,
-          hcard_url:   hcard_url,
-          seed_url:    seed_url,
-          profile_url: profile_url,
-          atom_url:    atom_url,
-          salmon_url:  salmon_url,
+          hcard_url:   parse_link(links, REL_HCARD),
+          seed_url:    parse_link(links, REL_SEED),
+          profile_url: parse_link(links, REL_PROFILE),
+          atom_url:    parse_link(links, REL_ATOM),
+          salmon_url:  parse_link(links, REL_SALMON),
 
           # TODO: remove me!  ##########
-          guid:        guid,
-          public_key:  Base64.strict_decode64(public_key)
+          guid:        parse_link(links, REL_GUID),
+          public_key:  (Base64.strict_decode64(public_key) if public_key)
         )
       end
 
@@ -172,10 +175,10 @@ module DiasporaFederation
       # @return [Hash] data XML data
       # @raise [InvalidData] if the given XML string is invalid or incomplete
       def self.parse_xml_and_validate(webfinger_xml)
-        data = XrdDocument.xml_data(webfinger_xml)
-        valid = data.key?(:subject) && data.key?(:aliases) && data.key?(:links)
-        raise InvalidData, "webfinger xml is incomplete" unless valid
-        data
+        XrdDocument.xml_data(webfinger_xml).tap do |data|
+          valid = data.key?(:subject) && data.key?(:aliases) && data.key?(:links)
+          raise InvalidData, "webfinger xml is incomplete" unless valid
+        end
       end
       private_class_method :parse_xml_and_validate
 
@@ -209,22 +212,9 @@ module DiasporaFederation
         ##################################
       end
 
-      def self.parse_links(data)
-        links = data[:links]
-        hcard   = parse_link(links, REL_HCARD)
-        seed    = parse_link(links, REL_SEED)
-        guid    = parse_link(links, REL_GUID)
-        profile = parse_link(links, REL_PROFILE)
-        atom    = parse_link(links, REL_ATOM)
-        salmon  = parse_link(links, REL_SALMON)
-        pubkey  = parse_link(links, REL_PUBKEY)
-        raise InvalidData, "webfinger xml is incomplete" unless [hcard, seed, guid, profile, atom, salmon, pubkey].all?
-        [hcard[:href], seed[:href], guid[:href], profile[:href], atom[:href], salmon[:href], pubkey[:href]]
-      end
-      private_class_method :parse_links
-
       def self.parse_link(links, rel)
-        links.find {|l| l[:rel] == rel }
+        element = links.find {|l| l[:rel] == rel }
+        element ? element[:href] : nil
       end
       private_class_method :parse_link
     end
diff --git a/lib/diaspora_federation/web_finger/xrd_document.rb b/lib/diaspora_federation/discovery/xrd_document.rb
similarity index 92%
rename from lib/diaspora_federation/web_finger/xrd_document.rb
rename to lib/diaspora_federation/discovery/xrd_document.rb
index d35fbe2..7e1a22a 100644
--- a/lib/diaspora_federation/web_finger/xrd_document.rb
+++ b/lib/diaspora_federation/discovery/xrd_document.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  module WebFinger
+  module Discovery
     # This class implements basic handling of XRD documents as far as it is
     # necessary in the context of the protocols used with Diaspora* federation.
     #
@@ -92,19 +92,18 @@ module DiasporaFederation
       # @raise [InvalidDocument] if the XRD is malformed
       def self.xml_data(xrd_doc)
         doc = parse_xrd_document(xrd_doc)
-        data = {}
 
-        exp_elem = doc.at_xpath("xrd:XRD/xrd:Expires", NS)
-        data[:expires] = DateTime.strptime(exp_elem.content, DATETIME_FORMAT) unless exp_elem.nil?
+        {}.tap do |data|
+          exp_elem = doc.at_xpath("xrd:XRD/xrd:Expires", NS)
+          data[:expires] = DateTime.strptime(exp_elem.content, DATETIME_FORMAT) unless exp_elem.nil?
 
-        subj_elem = doc.at_xpath("xrd:XRD/xrd:Subject", NS)
-        data[:subject] = subj_elem.content unless subj_elem.nil?
+          subj_elem = doc.at_xpath("xrd:XRD/xrd:Subject", NS)
+          data[:subject] = subj_elem.content unless subj_elem.nil?
 
-        parse_aliases_from_xml_doc(doc, data)
-        parse_properties_from_xml_doc(doc, data)
-        parse_links_from_xml_doc(doc, data)
-
-        data
+          parse_aliases_from_xml_doc(doc, data)
+          parse_properties_from_xml_doc(doc, data)
+          parse_links_from_xml_doc(doc, data)
+        end
       end
 
       private
diff --git a/lib/diaspora_federation/entities.rb b/lib/diaspora_federation/entities.rb
new file mode 100644
index 0000000..3665875
--- /dev/null
+++ b/lib/diaspora_federation/entities.rb
@@ -0,0 +1,12 @@
+module DiasporaFederation
+  # This namespace contains all the entities used to encapsulate data that is
+  # passed around in the Diaspora* network as part of the federation protocol.
+  #
+  # All entities must be defined in this namespace. otherwise the XML
+  # de-serialization will fail.
+  module Entities
+  end
+end
+
+require "diaspora_federation/entities/profile"
+require "diaspora_federation/entities/person"
diff --git a/lib/diaspora_federation/entities/person.rb b/lib/diaspora_federation/entities/person.rb
new file mode 100644
index 0000000..32a9080
--- /dev/null
+++ b/lib/diaspora_federation/entities/person.rb
@@ -0,0 +1,33 @@
+module DiasporaFederation
+  module Entities
+    # this entity contains the base data of a person
+    #
+    # @see Validators::PersonValidator
+    class Person < Entity
+      # @!attribute [r] guid
+      #   @see HCard#guid
+      #   @return [String] guid
+      property :guid
+
+      # @!attribute [r] diaspora_id
+      #   The diaspora ID of the person
+      #   @return [String] diaspora ID
+      property :diaspora_id, xml_name: :diaspora_handle
+
+      # @!attribute [r] url
+      #   @see WebFinger#seed_url
+      #   @return [String] link to the pod
+      property :url
+
+      # @!attribute [r] profile
+      #   all profile data of the person
+      #   @return [Profile] the profile of the person
+      entity :profile, Entities::Profile
+
+      # @!attribute [r] exported_key
+      #   @see HCard#public_key
+      #   @return [String] public key
+      property :exported_key
+    end
+  end
+end
diff --git a/lib/diaspora_federation/entities/profile.rb b/lib/diaspora_federation/entities/profile.rb
new file mode 100644
index 0000000..1ecdd35
--- /dev/null
+++ b/lib/diaspora_federation/entities/profile.rb
@@ -0,0 +1,54 @@
+module DiasporaFederation
+  module Entities
+    # this entity contains all the profile data of a person
+    #
+    # @see Validators::ProfileValidator
+    class Profile < Entity
+      # @!attribute [r] diaspora_id
+      #   The diaspora ID of the person
+      #   @see Person#diaspora_id
+      #   @return [String] diaspora ID
+      property :diaspora_id, xml_name: :diaspora_handle
+
+      # @!attribute [r] first_name
+      #   @deprecated
+      #   @see #full_name
+      #   @see HCard#first_name
+      #   @return [String] first name
+      property :first_name, default: nil
+
+      # @!attribute [r] last_name
+      #   @deprecated
+      #   @see #full_name
+      #   @see HCard#last_name
+      #   @return [String] last name
+      property :last_name, default: nil
+
+      # @!attribute [r] image_url
+      #   @see HCard#photo_large_url
+      #   @return [String] url to the big avatar (300x300)
+      property :image_url, default: nil
+      # @!attribute [r] image_url_medium
+      #   @see HCard#photo_medium_url
+      #   @return [String] url to the medium avatar (100x100)
+      property :image_url_medium, default: nil
+      # @!attribute [r] image_url_small
+      #   @see HCard#photo_small_url
+      #   @return [String] url to the small avatar (50x50)
+      property :image_url_small, default: nil
+
+      property :birthday, default: nil
+      property :gender, default: nil
+      property :bio, default: nil
+      property :location, default: nil
+
+      # @!attribute [r] searchable
+      #   @see HCard#searchable
+      #   @return [Boolean] searchable flag
+      property :searchable, default: true
+
+      property :nsfw, default: false
+      property :tag_string, default: nil
+    end
+  end
+end
diff --git a/lib/diaspora_federation/entity.rb b/lib/diaspora_federation/entity.rb
index fa3793f..86f980b 100644
--- a/lib/diaspora_federation/entity.rb
+++ b/lib/diaspora_federation/entity.rb
@@ -15,6 +15,7 @@ module DiasporaFederation
   #     property :prop
   #     property :optional, default: false
   #     property :dynamic_default, default: -> { Time.now }
+  #     property :another_prop, xml_name: :another_name
   #     entity :nested, NestedEntity
   #     entity :multiple, [OtherEntity]
   #   end
@@ -37,6 +38,12 @@ module DiasporaFederation
     # Initializes the Entity with the given attribute hash and freezes the created
     # instance it returns.
     #
+    # After creation, the entity is validated against a Validator, if one is defined.
+    # The Validator needs to be in the {DiasporaFederation::Validators} namespace and
+    # named like "<EntityName>Validator". Only valid entities can be created.
+    #
+    # @see DiasporaFederation::Validators
+    #
     # @note Attributes not defined as part of the class definition ({PropertiesDSL#property},
     #       {PropertiesDSL#entity}) get discarded silently.
     #
@@ -50,16 +57,18 @@ module DiasporaFederation
       end
 
       self.class.default_values.merge(data).each do |k, v|
-        instance_variable_set("@#{k}", v) if setable?(k, v)
+        instance_variable_set("@#{k}", nilify(v)) if setable?(k, v)
       end
+
       freeze
+      validate
     end
 
     # Returns a Hash representing this Entity (attributes => values)
     # @return [Hash] entity data (mostly equal to the hash used for initialization).
     def to_h
       self.class.class_prop_names.each_with_object({}) do |prop, hash|
-        hash[prop] = send(prop)
+        hash[prop] = public_send(prop)
       end
     end
 
@@ -76,16 +85,12 @@ module DiasporaFederation
 
     # some of this is from Rails "Inflector.demodulize" and "Inflector.undersore"
     def self.entity_name
-      word = name.dup
-      i = word.rindex("::")
-      word = word[(i + 2)..-1] if i
-
-      word.gsub!("::", "/")
-      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2')
-      word.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
-      word.tr!("-", "_")
-      word.downcase!
-      word
+      name.rpartition("::").last.tap do |word|
+        word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2')
+        word.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
+        word.tr!("-", "_")
+        word.downcase!
+      end
     end
 
     private
@@ -113,34 +118,61 @@ module DiasporaFederation
         val.all? {|v| v.instance_of?(t.first) })
     end
 
+    def nilify(value)
+      return nil if value.respond_to?(:empty?) && value.empty?
+      value
+    end
+
+    def validate
+      validator_name = "DiasporaFederation::Validators::#{self.class.name.split('::').last}Validator"
+      return unless Validators.const_defined? validator_name
+
+      validator_class = Validators.const_get validator_name
+      validator = validator_class.new self
+      raise ValidationError, error_message(validator) unless validator.valid?
+    end
+
+    def error_message(validator)
+      errors = validator.errors.map do |prop, rule|
+        "property: #{prop}, value: #{public_send(prop).inspect}, rule: #{rule[:rule]}, with params: #{rule[:params]}"
+      end
+      "Failed validation for properties: #{errors.join(' | ')}"
+    end
+
     # Serialize the Entity into XML elements
     # @return [Nokogiri::XML::Element] root node
     def entity_xml
       doc = Nokogiri::XML::DocumentFragment.new(Nokogiri::XML::Document.new)
-      root_element = Nokogiri::XML::Element.new(self.class.entity_name, doc)
-
-      self.class.class_props.each do |prop_def|
-        name = prop_def[:name]
-        type = prop_def[:type]
-        if type == String
-          root_element << simple_node(doc, name)
-        else
-          # call #to_xml for each item and append to root
-          [*send(name)].compact.each do |item|
-            root_element << item.to_xml
-          end
+      Nokogiri::XML::Element.new(self.class.entity_name, doc).tap do |root_element|
+        self.class.class_props.each do |prop_def|
+          add_property_to_xml(doc, prop_def, root_element)
         end
       end
+    end
 
-      root_element
+    def add_property_to_xml(doc, prop_def, root_element)
+      property = prop_def[:name]
+      type = prop_def[:type]
+      if type == String
+        root_element << simple_node(doc, prop_def[:xml_name], property)
+      else
+        # call #to_xml for each item and append to root
+        [*public_send(property)].compact.each do |item|
+          root_element << item.to_xml
+        end
+      end
     end
 
     # create simple node, fill it with text and append to root
-    def simple_node(doc, name)
-      node = Nokogiri::XML::Element.new(name.to_s, doc)
-      data = send(name).to_s
-      node.content = data unless data.empty?
-      node
+    def simple_node(doc, name, property)
+      Nokogiri::XML::Element.new(name.to_s, doc).tap do |node|
+        data = public_send(property).to_s
+        node.content = data unless data.empty?
+      end
+    end
+
+    # Raised, if entity is not valid
+    class ValidationError < RuntimeError
     end
   end
 end
diff --git a/lib/diaspora_federation/fetcher.rb b/lib/diaspora_federation/fetcher.rb
new file mode 100644
index 0000000..4ece8eb
--- /dev/null
+++ b/lib/diaspora_federation/fetcher.rb
@@ -0,0 +1,42 @@
+require "faraday"
+require "faraday_middleware/response/follow_redirects"
+require "typhoeus/adapters/faraday"
+
+module DiasporaFederation
+  # A wrapper for {https://github.com/lostisland/faraday Faraday} used for
+  # fetching
+  #
+  # @see Discovery::Discovery
+  class Fetcher
+    # Perform a GET request
+    #
+    # @param [String] uri the URI
+    # @return [Faraday::Response] the response
+    def self.get(uri)
+      connection.get(uri)
+    end
+
+    # gets the Faraday connection
+    #
+    # @return [Faraday::Connection] the response
+    def self.connection
+      create_default_connection unless @connection
+      @connection.dup
+    end
+
+    def self.create_default_connection
+      options = {
+        request: {timeout: 30},
+        ssl:     {ca_file: DiasporaFederation.certificate_authorities}
+      }
+
+      @connection = Faraday::Connection.new(options) do |builder|
+        builder.use FaradayMiddleware::FollowRedirects, limit: 4
+        builder.adapter :typhoeus
+      end
+
+      @connection.headers["User-Agent"] = "DiasporaFederation/#{DiasporaFederation::VERSION}"
+    end
+    private_class_method :create_default_connection
+  end
+end
diff --git a/lib/diaspora_federation/logging.rb b/lib/diaspora_federation/logging.rb
index 125415c..615e0e2 100644
--- a/lib/diaspora_federation/logging.rb
+++ b/lib/diaspora_federation/logging.rb
@@ -13,10 +13,12 @@ module DiasporaFederation
                     # use logging-gem if available
                     return ::Logging::Logger[self] if defined?(::Logging::Logger)
 
+                    # use rails logger if running in rails and no logging-gem is available
+                    return ::Rails.logger if defined?(::Rails)
+
                     # fallback logger
                     @logger = Logger.new(STDOUT)
-                    loglevel = defined?(::Rails) ? ::Rails.configuration.log_level.to_s.upcase : "INFO"
-                    @logger.level = Logger.const_get(loglevel)
+                    @logger.level = Logger::INFO
                     @logger
                   end
     end
diff --git a/lib/diaspora_federation/properties_dsl.rb b/lib/diaspora_federation/properties_dsl.rb
index abfb9fb..12525d7 100644
--- a/lib/diaspora_federation/properties_dsl.rb
+++ b/lib/diaspora_federation/properties_dsl.rb
@@ -6,6 +6,7 @@ module DiasporaFederation
   #   property :prop
   #   property :optional, default: false
   #   property :dynamic_default, default: -> { Time.now }
+  #   property :another_prop, xml_name: :another_name
   #   entity :nested, NestedEntity
   #   entity :multiple, [OtherEntity]
   module PropertiesDSL
@@ -19,6 +20,7 @@ module DiasporaFederation
     # @param [Hash] opts further options
     # @option opts [Object, #call] :default a default value, making the
     #   property optional
+    # @option opts [Symbol] :xml_name another name used for xml generation
     def property(name, opts={})
       define_property name, String, opts
     end
@@ -69,7 +71,14 @@ module DiasporaFederation
     def define_property(name, type, opts={})
       raise InvalidName unless name_valid?(name)
 
-      class_props << {name: name, type: type}
+      xml_name = name
+      if opts.has_key? :xml_name
+        raise ArgumentError, "xml_name is not supported for nested entities" unless type == String
+        xml_name = opts[:xml_name]
+        raise InvalidName, "invalid xml_name" unless name_valid?(xml_name)
+      end
+
+      class_props << {name: name, xml_name: xml_name, type: type}
       default_props[name] = opts[:default] if opts.has_key? :default
 
       instance_eval { attr_reader name }
@@ -79,7 +88,7 @@ module DiasporaFederation
     # @param [String, Symbol] name the name to check
     # @return [Boolean]
     def name_valid?(name)
-      name.instance_of?(Symbol) || name.instance_of?(String)
+      name.instance_of?(Symbol)
     end
 
     # checks if the type extends {Entity}
diff --git a/lib/diaspora_federation/validators.rb b/lib/diaspora_federation/validators.rb
new file mode 100644
index 0000000..4371747
--- /dev/null
+++ b/lib/diaspora_federation/validators.rb
@@ -0,0 +1,38 @@
+require "validation"
+require "validation/rule/regular_expression"
+require "validation/rule/not_empty"
+require "validation/rule/uri"
+
+# +valid+ gem namespace
+module Validation
+  # This module contains custom validation rules for various data field types.
+  # That includes types for which there are no provided rules by the +valid+ gem
+  # or types that are very specific to Diaspora* federation and need special handling.
+  # The rules are used inside the {DiasporaFederation::Validators validator classes}
+  # to perform basic sanity-checks on {DiasporaFederation::Entities federation entities}.
+  module Rule
+  end
+end
+
+require "diaspora_federation/validators/rules/birthday"
+require "diaspora_federation/validators/rules/boolean"
+require "diaspora_federation/validators/rules/diaspora_id"
+require "diaspora_federation/validators/rules/guid"
+require "diaspora_federation/validators/rules/nilable_uri"
+require "diaspora_federation/validators/rules/not_nil"
+require "diaspora_federation/validators/rules/public_key"
+require "diaspora_federation/validators/rules/tag_count"
+
+module DiasporaFederation
+  # Validators to perform basic sanity-checks on {DiasporaFederation::Entities federation entities}.
+  #
+  # The Validators are mapped with the entities by name. The naming schema
+  # is "<EntityName>Validator".
+  module Validators
+  end
+end
+
+require "diaspora_federation/validators/h_card_validator"
+require "diaspora_federation/validators/person_validator"
+require "diaspora_federation/validators/profile_validator"
+require "diaspora_federation/validators/web_finger_validator"
diff --git a/lib/diaspora_federation/validators/h_card_validator.rb b/lib/diaspora_federation/validators/h_card_validator.rb
new file mode 100644
index 0000000..029f244
--- /dev/null
+++ b/lib/diaspora_federation/validators/h_card_validator.rb
@@ -0,0 +1,30 @@
+module DiasporaFederation
+  module Validators
+    # This validates a {Discovery::HCard}
+    #
+    # @todo activate guid and public key validation after all pod have it in
+    #   the hcard.
+    #
+    # @note
+    class HCardValidator < Validation::Validator
+      include Validation
+
+      # rule :guid, :guid
+
+      # the name must not contain a semicolon because of mentions
+      # @{<full_name> ; <diaspora_id>}
+      rule :full_name, regular_expression: {regex: /\A[^;]{,70}\z/}
+      rule :first_name, regular_expression: {regex: /\A[^;]{,32}\z/}
+      rule :last_name, regular_expression: {regex: /\A[^;]{,32}\z/}
+
+      # this urls can be relative
+      rule :photo_large_url, [:not_nil, nilableURI: [:path]]
+      rule :photo_medium_url, [:not_nil, nilableURI: [:path]]
+      rule :photo_small_url, [:not_nil, nilableURI: [:path]]
+
+      # rule :exported_key, :public_key
+
+      rule :searchable, :boolean
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/person_validator.rb b/lib/diaspora_federation/validators/person_validator.rb
new file mode 100644
index 0000000..f344f9e
--- /dev/null
+++ b/lib/diaspora_federation/validators/person_validator.rb
@@ -0,0 +1,18 @@
+module DiasporaFederation
+  module Validators
+    # This validates a {Entities::Person}
+    class PersonValidator < Validation::Validator
+      include Validation
+
+      rule :guid, :guid
+
+      rule :diaspora_id, :diaspora_id
+
+      rule :url, %i(not_nil nilableURI)
+
+      rule :profile, :not_nil
+
+      rule :exported_key, :public_key
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/profile_validator.rb b/lib/diaspora_federation/validators/profile_validator.rb
new file mode 100644
index 0000000..773ee97
--- /dev/null
+++ b/lib/diaspora_federation/validators/profile_validator.rb
@@ -0,0 +1,33 @@
+module DiasporaFederation
+  module Validators
+    # This validates a {Entities::Profile}
+    class ProfileValidator < Validation::Validator
+      include Validation
+
+      rule :diaspora_id, :diaspora_id
+
+      # the name must not contain a semicolon because of mentions
+      # @{<full_name> ; <diaspora_id>}
+      rule :first_name, regular_expression: {regex: /\A[^;]{,32}\z/}
+      rule :last_name, regular_expression: {regex: /\A[^;]{,32}\z/}
+
+      # this urls can be relative
+      rule :image_url, nilableURI: [:path]
+      rule :image_url_medium, nilableURI: [:path]
+      rule :image_url_small, nilableURI: [:path]
+
+      rule :birthday, :birthday
+
+      # TODO: replace regex with "length: {maximum: xxx}" but this rule doesn't allow nil now.
+      rule :gender, regular_expression: {regex: /\A.{,255}\z/}
+      rule :bio, regular_expression: {regex: /\A.{,65535}\z/}
+      rule :location, regular_expression: {regex: /\A.{,255}\z/}
+
+      rule :searchable, :boolean
+
+      rule :nsfw, :boolean
+
+      rule :tag_string, tag_count: {maximum: 5}
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/birthday.rb b/lib/diaspora_federation/validators/rules/birthday.rb
new file mode 100644
index 0000000..682719c
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/birthday.rb
@@ -0,0 +1,38 @@
+require "date"
+
+module Validation
+  module Rule
+    # Birthday validation rule
+    #
+    # Valid is:
+    # * nil or an empty +String+
+    # * a +Date+ object
+    # * a +String+ with the format "yyyy-mm-dd" and is a valid +Date+, example: 2015-07-25
+    class Birthday
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :birthday
+      end
+
+      # Determines if value is a valid birthday date
+      def valid_value?(value)
+        return true if value.nil? || (value.is_a?(String) && value.empty?)
+        return true if value.is_a? Date
+
+        if value =~ /[0-9]{4}\-[0-9]{2}\-[0-9]{2}/
+          date_field = value.split("-").map(&:to_i)
+          return Date.valid_civil?(date_field[0], date_field[1], date_field[2])
+        end
+
+        false
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/boolean.rb b/lib/diaspora_federation/validators/rules/boolean.rb
new file mode 100644
index 0000000..f2f4918
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/boolean.rb
@@ -0,0 +1,38 @@
+module Validation
+  module Rule
+    # Boolean validation rule
+    #
+    # Valid is:
+    # * a +String+: "true", "false", "t", "f", "yes", "no", "y", "n", "1", "0"
+    # * a +Fixnum+: 1 or 0
+    # * a +Boolean+: true or false
+    class Boolean
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :boolean
+      end
+
+      # Determines if value is a valid +boolean+
+      def valid_value?(value)
+        return false if value.nil?
+
+        if value.is_a?(String)
+          true if value =~ /\A(true|false|t|f|yes|no|y|n|1|0)\z/i
+        elsif value.is_a?(Fixnum)
+          true if value == 1 || value == 0
+        elsif [true, false].include? value
+          true
+        else
+          false
+        end
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/diaspora_id.rb b/lib/diaspora_federation/validators/rules/diaspora_id.rb
new file mode 100644
index 0000000..591c621
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/diaspora_id.rb
@@ -0,0 +1,46 @@
+module Validation
+  module Rule
+    # Diaspora ID validation rule
+    #
+    # This rule is based on https://github.com/zombor/Validator/blob/master/lib/validation/rule/email.rb
+    # which was adapted from https://github.com/emmanuel/aequitas/blob/master/lib/aequitas/rule/format/email_address.rb
+    class DiasporaId
+      # The Regex for a valid diaspora ID
+      DIASPORA_ID = begin
+        letter         = "a-zA-Z"
+        digit          = "0-9"
+        username       = "[#{letter}#{digit}\-\_\.]+"
+        atext          = "[#{letter}#{digit}+\=\-\_]"
+        dot_atom       = "#{atext}+([.]#{atext}*)*"
+        no_ws_ctl      = '\x01-\x08\x11\x12\x14-\x1f\x7f'
+        text           = '[\x01-\x09\x11\x12\x14-\x7f]'
+        quoted_pair    = "(\\x5c#{text})"
+        dtext          = "[#{no_ws_ctl}\\x21-\\x5a\\x5e-\\x7e]"
+        dcontent       = "(?:#{dtext}|#{quoted_pair})"
+        domain_literal = "\\[#{dcontent}+\\]"
+        domain         = "(?:#{dot_atom}|#{domain_literal})"
+        port           = "(:[#{digit}]+)?"
+        addr_spec      = "#{username}\@#{domain}#{port}"
+
+        /\A#{addr_spec}\z/u
+      end
+
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :diaspora_id
+      end
+
+      # Determines if value is a valid diaspora ID
+      def valid_value?(value)
+        !DIASPORA_ID.match(value).nil?
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/guid.rb b/lib/diaspora_federation/validators/rules/guid.rb
new file mode 100644
index 0000000..73077fa
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/guid.rb
@@ -0,0 +1,28 @@
+module Validation
+  module Rule
+    # GUID validation rule
+    #
+    # Valid is a +String+ that is at least 16 chars long and contains only:
+    # * Letters: a-z
+    # * Numbers: 0-9
+    # * Special chars: '-', '_', '@', '.' and ':'
+    class Guid
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :guid
+      end
+
+      # Determines if value is a valid +GUID+
+      def valid_value?(value)
+        value.is_a?(String) && value.downcase =~ /\A[0-9a-z\-_@.:]{16,}\z/
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/nilable_uri.rb b/lib/diaspora_federation/validators/rules/nilable_uri.rb
new file mode 100644
index 0000000..727d460
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/nilable_uri.rb
@@ -0,0 +1,19 @@
+module Validation
+  module Rule
+    # URI validation rule
+
+    # It allows +nil+, so maybe add an additional {Rule::NotNil} rule.
+    class NilableURI < Validation::Rule::URI
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :nilableURI
+      end
+
+      # Determines if value is a valid URI
+      def valid_value?(uri_string)
+        uri_string.nil? || super
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/not_nil.rb b/lib/diaspora_federation/validators/rules/not_nil.rb
new file mode 100644
index 0000000..8d37d7e
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/not_nil.rb
@@ -0,0 +1,23 @@
+module Validation
+  module Rule
+    # Validates that a property is not +nil+
+    class NotNil
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :not_nil
+      end
+
+      # Determines if value is not nil
+      def valid_value?(value)
+        !value.nil?
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/public_key.rb b/lib/diaspora_federation/validators/rules/public_key.rb
new file mode 100644
index 0000000..8601fc9
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/public_key.rb
@@ -0,0 +1,33 @@
+module Validation
+  module Rule
+    # Public key validation rule
+    #
+    # A valid key must:
+    # * start with "-----BEGIN PUBLIC KEY-----" and end with "-----END PUBLIC KEY-----"
+    # or
+    # * start with "-----BEGIN RSA PUBLIC KEY-----" and end with "-----END RSA PUBLIC KEY-----"
+    class PublicKey
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :public_key
+      end
+
+      # Determines if value is a valid public key
+      def valid_value?(value)
+        !value.nil? && (
+          (value.strip.start_with?("-----BEGIN PUBLIC KEY-----") &&
+           value.strip.end_with?("-----END PUBLIC KEY-----")) ||
+          (value.strip.start_with?("-----BEGIN RSA PUBLIC KEY-----") &&
+            value.strip.end_with?("-----END RSA PUBLIC KEY-----"))
+        )
+      end
+
+      # This rule has no params
+      # @return [Hash] params
+      def params
+        {}
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/rules/tag_count.rb b/lib/diaspora_federation/validators/rules/tag_count.rb
new file mode 100644
index 0000000..6f100a8
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/tag_count.rb
@@ -0,0 +1,33 @@
+module Validation
+  module Rule
+    # Rule for validating the number of tags in a string.
+    # Only the "#" characters will be counted.
+    # The string can be nil.
+    class TagCount
+      # This rule must have a +maximum+ param
+      # @return [Hash] params
+      attr_reader :params
+
+      # @param [Hash] params
+      # @option params [Fixnum] :maximum maximum allowed tag count
+      def initialize(params)
+        unless params.include?(:maximum) && params[:maximum].is_a?(Fixnum)
+          raise ArgumentError, "A number has to be specified for :maximum"
+        end
+
+        @params = params
+      end
+
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :tag_count
+      end
+
+      # Determines if value doesn't have more than +maximum+ tags
+      def valid_value?(value)
+        value.nil? || value.count("#") <= params[:maximum]
+      end
+    end
+  end
+end
diff --git a/lib/diaspora_federation/validators/web_finger_validator.rb b/lib/diaspora_federation/validators/web_finger_validator.rb
new file mode 100644
index 0000000..a6aa397
--- /dev/null
+++ b/lib/diaspora_federation/validators/web_finger_validator.rb
@@ -0,0 +1,20 @@
+module DiasporaFederation
+  module Validators
+    # This validates a {Discovery::WebFinger}
+    #
+    # @note it does not validate the guid and public key, because it will be
+    #   removed in the webfinger
+    class WebFingerValidator < Validation::Validator
+      include Validation
+
+      rule :acct_uri, :not_empty
+
+      rule :alias_url, [:not_nil, nilableURI: %i(host path)]
+      rule :hcard_url, [:not_nil, nilableURI: %i(host path)]
+      rule :seed_url, %i(not_nil nilableURI)
+      rule :profile_url, [:not_nil, nilableURI: %i(host path)]
+      rule :atom_url, [:not_nil, nilableURI: %i(host path)]
+      rule :salmon_url, [:not_nil, nilableURI: %i(host path)]
+    end
+  end
+end
diff --git a/lib/diaspora_federation/web_finger.rb b/lib/diaspora_federation/web_finger.rb
deleted file mode 100644
index f0d6222..0000000
--- a/lib/diaspora_federation/web_finger.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-module DiasporaFederation
-  # This module provides the namespace for the various classes implementing
-  # WebFinger and other protocols used for metadata discovery on remote servers
-  # in the Diaspora* network.
-  module WebFinger
-  end
-end
-
-require "diaspora_federation/web_finger/exceptions"
-require "diaspora_federation/web_finger/xrd_document"
-require "diaspora_federation/web_finger/host_meta"
-require "diaspora_federation/web_finger/web_finger"
-require "diaspora_federation/web_finger/h_card"
diff --git a/script/ci/travis.sh b/script/ci/travis.sh
deleted file mode 100755
index 39cb575..0000000
--- a/script/ci/travis.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/bin/sh
-
-command="bundle exec rake --trace"
-exec $command
diff --git a/spec/controllers/diaspora_federation/webfinger_controller_spec.rb b/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
index 62b42cb..98d5949 100644
--- a/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
+++ b/spec/controllers/diaspora_federation/webfinger_controller_spec.rb
@@ -24,13 +24,13 @@ module DiasporaFederation
         expect(response.header["Content-Type"]).to include "application/xrd+xml"
       end
 
-      it "calls WebFinger::HostMeta.from_base_url with the base url" do
-        expect(WebFinger::HostMeta).to receive(:from_base_url).with("http://localhost:3000/").and_call_original
+      it "calls Discovery::HostMeta.from_base_url with the base url" do
+        expect(Discovery::HostMeta).to receive(:from_base_url).with("http://localhost:3000/").and_call_original
         get :host_meta
       end
 
       it "caches the xml" do
-        expect(WebFinger::HostMeta).to receive(:from_base_url).exactly(1).times.and_call_original
+        expect(Discovery::HostMeta).to receive(:from_base_url).exactly(1).times.and_call_original
         get :host_meta
         get :host_meta
       end
@@ -48,7 +48,7 @@ module DiasporaFederation
         expect(response).to be_success
       end
 
-      it "contains the diaspora handle" do
+      it "contains the diaspora id" do
         get :legacy_webfinger, "q" => "acct:alice@localhost:3000"
         expect(response.body).to include "<Subject>acct:alice@localhost:3000</Subject>"
       end
diff --git a/spec/entities.rb b/spec/entities.rb
index 486a8a6..2ecb901 100644
--- a/spec/entities.rb
+++ b/spec/entities.rb
@@ -1,22 +1,39 @@
-module Entities
-  class TestEntity < DiasporaFederation::Entity
-    property :test
+module DiasporaFederation
+  module Entities
+    class TestEntity < DiasporaFederation::Entity
+      property :test
+    end
+
+    class TestDefaultEntity < DiasporaFederation::Entity
+      property :test1
+      property :test2
+      property :test3, default: true
+      property :test4, default: -> { true }
+    end
+
+    class OtherEntity < DiasporaFederation::Entity
+      property :asdf
+    end
+
+    class TestNestedEntity < DiasporaFederation::Entity
+      property :asdf
+      entity :test, TestEntity
+      entity :multi, [OtherEntity]
+    end
+
+    class TestEntityWithXmlName < DiasporaFederation::Entity
+      property :test
+      property :qwer, xml_name: :asdf
+    end
   end
 
-  class TestDefaultEntity < DiasporaFederation::Entity
-    property :test1
-    property :test2
-    property :test3, default: true
-    property :test4, default: -> { true }
-  end
+  module Validators
+    class TestDefaultEntityValidator < Validation::Validator
+      include Validation
 
-  class OtherEntity < DiasporaFederation::Entity
-    property :asdf
-  end
-
-  class TestNestedEntity < DiasporaFederation::Entity
-    property :asdf
-    entity :test, TestEntity
-    entity :multi, [OtherEntity]
+      rule :test1, regular_expression: {regex: /\A[^;]{,32}\z/}
+      rule :test2, :not_nil
+      rule :test3, :boolean
+    end
   end
 end
diff --git a/spec/factories.rb b/spec/factories.rb
index 88173c4..8d53271 100644
--- a/spec/factories.rb
+++ b/spec/factories.rb
@@ -5,12 +5,69 @@ def r_str
 end
 
 FactoryGirl.define do
+  sequence(:guid) { UUID.generate :compact }
+  sequence(:diaspora_id) {|n| "person-#{n}-#{r_str}@localhost:3000" }
+  sequence(:public_key) { OpenSSL::PKey::RSA.generate(1024).public_key.export }
+
   factory :person do
-    sequence(:diaspora_handle) {|n| "person-#{n}-#{r_str}@localhost:3000" }
+    diaspora_id
     url "http://localhost:3000/"
-    serialized_public_key OpenSSL::PKey::RSA.generate(1024).public_key.export
+    serialized_public_key { generate(:public_key) }
     after(:create) do |u|
       u.save
     end
   end
+
+  factory :webfinger, class: DiasporaFederation::Discovery::WebFinger do
+    guid
+    acct_uri { "acct:#{generate(:diaspora_id)}" }
+    alias_url "http://localhost:3000/people/0123456789abcdef"
+    hcard_url "http://localhost:3000/hcard/users/user"
+    seed_url "http://localhost:3000/"
+    profile_url "http://localhost:3000/u/user"
+    atom_url "http://localhost:3000/public/user.atom"
+    salmon_url "http://localhost:3000/receive/users/0123456789abcdef"
+    public_key
+  end
+
+  factory :h_card, class: DiasporaFederation::Discovery::HCard do
+    guid
+    nickname "some_name"
+    full_name "my name"
+    first_name "my name"
+    last_name nil
+    url "http://localhost:3000/"
+    public_key
+    photo_large_url "/assets/user/default.png"
+    photo_medium_url "/assets/user/default.png"
+    photo_small_url "/assets/user/default.png"
+    searchable true
+  end
+
+  factory :person_entity, class: DiasporaFederation::Entities::Person do
+    guid
+    diaspora_id
+    url "http://localhost:3000/"
+    exported_key { generate(:public_key) }
+    profile {
+      DiasporaFederation::Entities::Profile.new(
+        FactoryGirl.attributes_for(:profile_entity, diaspora_id: diaspora_id))
+    }
+  end
+
+  factory :profile_entity, class: DiasporaFederation::Entities::Profile do
+    diaspora_id
+    first_name "my name"
+    last_name nil
+    image_url "/assets/user/default.png"
+    image_url_medium "/assets/user/default.png"
+    image_url_small "/assets/user/default.png"
+    birthday "1988-07-15"
+    gender "Male"
+    bio "some text about me"
+    location "github"
+    searchable true
+    nsfw false
+    tag_string "#i #love #tags"
+  end
 end
diff --git a/spec/lib/diaspora_federation/discovery/discovery_spec.rb b/spec/lib/diaspora_federation/discovery/discovery_spec.rb
new file mode 100644
index 0000000..e70c933
--- /dev/null
+++ b/spec/lib/diaspora_federation/discovery/discovery_spec.rb
@@ -0,0 +1,192 @@
+module DiasporaFederation
+  describe Discovery::Discovery do
+    let(:host_meta_xrd) { FixtureGeneration.load_fixture("host-meta") }
+    let(:webfinger_xrd) { FixtureGeneration.load_fixture("legacy-webfinger") }
+    let(:hcard_html) { FixtureGeneration.load_fixture("hcard") }
+    let(:account) { alice.diaspora_id }
+    let(:default_image) { "http://localhost:3000/assets/user/default.png" }
+
+    describe "#intialize" do
+      it "sets diaspora id" do
+        discovery = Discovery::Discovery.new("some_user@example.com")
+        expect(discovery.diaspora_id).to eq("some_user@example.com")
+      end
+
+      it "downcases account and strips whitespace, and sub 'acct:'" do
+        discovery = Discovery::Discovery.new("acct:BIGBOY@Example.Com ")
+        expect(discovery.diaspora_id).to eq("bigboy@example.com")
+      end
+    end
+
+    describe ".fetch" do
+      it "fetches the userdata and returns a person object" do
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 200, body: webfinger_xrd)
+        stub_request(:get, "http://localhost:3000/hcard/users/#{alice.guid}")
+          .to_return(status: 200, body: hcard_html)
+
+        person = Discovery::Discovery.new(account).fetch
+
+        expect(person.guid).to eq(alice.guid)
+        expect(person.diaspora_id).to eq(account)
+        expect(person.url).to eq(alice.url)
+        expect(person.exported_key).to eq(alice.serialized_public_key)
+
+        profile = person.profile
+
+        expect(profile.diaspora_id).to eq(alice.diaspora_id)
+        expect(profile.first_name).to eq("Dummy")
+        expect(profile.last_name).to eq("User")
+
+        expect(profile.image_url).to eq(default_image)
+        expect(profile.image_url_medium).to eq(default_image)
+        expect(profile.image_url_small).to eq(default_image)
+      end
+
+      it "falls back to http if https fails with 404" do
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_return(status: 404)
+        stub_request(:get, "http://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 200, body: webfinger_xrd)
+        stub_request(:get, "http://localhost:3000/hcard/users/#{alice.guid}")
+          .to_return(status: 200, body: hcard_html)
+
+        person = Discovery::Discovery.new(account).fetch
+
+        expect(person.guid).to eq(alice.guid)
+        expect(person.diaspora_id).to eq(account)
+      end
+
+      it "falls back to http if https fails with ssl error" do
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_raise(OpenSSL::SSL::SSLError)
+        stub_request(:get, "http://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 200, body: webfinger_xrd)
+        stub_request(:get, "http://localhost:3000/hcard/users/#{alice.guid}")
+          .to_return(status: 200, body: hcard_html)
+
+        person = Discovery::Discovery.new(account).fetch
+
+        expect(person.guid).to eq(alice.guid)
+        expect(person.diaspora_id).to eq(account)
+      end
+
+      it "fails if the diaspora id does not match" do
+        modified_webfinger = webfinger_xrd.gsub(account, "anonther_user@example.com")
+
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 200, body: modified_webfinger)
+
+        expect { Discovery::Discovery.new(account).fetch }.to raise_error Discovery::DiscoveryError
+      end
+
+      it "fails if the diaspora id was not found" do
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 404)
+
+        expect { Discovery::Discovery.new(account).fetch }.to raise_error Discovery::DiscoveryError
+      end
+
+      it "reads old hcard without guid and public key" do
+        historic_hcard_html = <<-HTML
+<div id="content">
+<h1>#{account}</h1>
+<div id="content_inner">
+<div class="entity_profile vcard author" id="i">
+<h2>User profile</h2>
+<dl class="entity_nickname">
+<dt>Nickname</dt>
+<dd>
+<a class="nickname url uid" href="#{alice.url}" rel="me"></a>
+</dd>
+</dl>
+<dl class="entity_given_name">
+<dt>First name</dt>
+<dd>
+<span class="given_name"></span>
+</dd>
+</dl>
+<dl class="entity_family_name">
+<dt>Family name</dt>
+<dd>
+<span class="family_name"></span>
+</dd>
+</dl>
+<dl class="entity_fn">
+<dt>Full name</dt>
+<dd>
+<span class="fn"></span>
+</dd>
+</dl>
+<dl class="entity_url">
+<dt>URL</dt>
+<dd>
+<a class="url" href="#{alice.url}" id="pod_location" rel="me">#{alice.url}</a>
+</dd>
+</dl>
+<dl class="entity_photo">
+<dt>Photo</dt>
+<dd>
+<img class="photo avatar" height="300px" src="#{default_image}" width="300px">
+</dd>
+</dl>
+<dl class="entity_photo_medium">
+<dt>Photo</dt>
+<dd>
+<img class="photo avatar" height="100px" src="#{default_image}" width="100px">
+</dd>
+</dl>
+<dl class="entity_photo_small">
+<dt>Photo</dt>
+<dd>
+<img class="photo avatar" height="50px" src="#{default_image}" width="50px">
+</dd>
+</dl>
+<dl class="entity_searchable">
+<dt>Searchable</dt>
+<dd>
+<span class="searchable">true</span>
+</dd>
+</dl>
+</div>
+</div>
+</div>
+        HTML
+
+        stub_request(:get, "https://localhost:3000/.well-known/host-meta")
+          .to_return(status: 200, body: host_meta_xrd)
+        stub_request(:get, "http://localhost:3000/webfinger?q=acct:#{account}")
+          .to_return(status: 200, body: webfinger_xrd)
+        stub_request(:get, "http://localhost:3000/hcard/users/#{alice.guid}")
+          .to_return(status: 200, body: historic_hcard_html)
+
+        person = Discovery::Discovery.new(account).fetch
+
+        expect(person.guid).to eq(alice.guid)
+        expect(person.diaspora_id).to eq(account)
+        expect(person.url).to eq(alice.url)
+        expect(person.exported_key).to eq(alice.serialized_public_key)
+
+        profile = person.profile
+
+        expect(profile.diaspora_id).to eq(alice.diaspora_id)
+        expect(profile.first_name).to be_nil
+        expect(profile.last_name).to be_nil
+
+        expect(profile.image_url).to eq(default_image)
+        expect(profile.image_url_medium).to eq(default_image)
+        expect(profile.image_url_small).to eq(default_image)
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/web_finger/h_card_spec.rb b/spec/lib/diaspora_federation/discovery/h_card_spec.rb
similarity index 78%
rename from spec/lib/diaspora_federation/web_finger/h_card_spec.rb
rename to spec/lib/diaspora_federation/discovery/h_card_spec.rb
index c7e124a..687645a 100644
--- a/spec/lib/diaspora_federation/web_finger/h_card_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/h_card_spec.rb
@@ -1,10 +1,27 @@
 module DiasporaFederation
-  describe WebFinger::HCard do
+  describe Discovery::HCard do
     let(:person) { FactoryGirl.create(:person) }
     let(:photo_large_url) { "#{person.url}/upload/large.png" }
     let(:photo_medium_url) { "#{person.url}/upload/medium.png" }
     let(:photo_small_url) { "#{person.url}/upload/small.png" }
 
+    let(:data) {
+      {
+        guid:             person.guid,
+        nickname:         person.nickname,
+        full_name:        person.full_name,
+        url:              person.url,
+        photo_large_url:  photo_large_url,
+        photo_medium_url: photo_medium_url,
+        photo_small_url:  photo_small_url,
+        public_key:       person.serialized_public_key,
+        searchable:       person.searchable,
+        first_name:       person.first_name,
+        last_name:        person.last_name
+      }
+    }
+    let(:klass) { Discovery::HCard }
+
     let(:html) {
       <<-HTML
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
@@ -92,36 +109,18 @@ module DiasporaFederation
 HTML
     }
 
-    it "must not create blank instances" do
-      expect { WebFinger::HCard.new({}) }.to raise_error ArgumentError
-    end
+    it_behaves_like "an Entity subclass"
 
     context "generation" do
       it "creates an instance from a data hash" do
-        hcard = WebFinger::HCard.new(
-          guid:             person.guid,
-          nickname:         person.nickname,
-          full_name:        person.full_name,
-          url:              person.url,
-          photo_large_url:  photo_large_url,
-          photo_medium_url: photo_medium_url,
-          photo_small_url:  photo_small_url,
-          public_key:       person.serialized_public_key,
-          searchable:       person.searchable,
-          first_name:       person.first_name,
-          last_name:        person.last_name
-        )
+        hcard = Discovery::HCard.new(data)
         expect(hcard.to_html).to eq(html)
       end
-
-      it "fails if nil was given" do
-        expect { WebFinger::HCard.new(nil) }.to raise_error ArgumentError, "expected a Hash"
-      end
     end
 
     context "parsing" do
       it "reads its own output" do
-        hcard = WebFinger::HCard.from_html(html)
+        hcard = Discovery::HCard.from_html(html)
         expect(hcard.guid).to eq(person.guid)
         expect(hcard.nickname).to eq(person.nickname)
         expect(hcard.full_name).to eq(person.full_name)
@@ -137,7 +136,7 @@ HTML
       end
 
       it "is frozen after parsing" do
-        hcard = WebFinger::HCard.from_html(html)
+        hcard = Discovery::HCard.from_html(html)
         expect(hcard).to be_frozen
       end
 
@@ -147,11 +146,30 @@ HTML
           "class=\"searchable\"><"
         )
 
-        hcard = WebFinger::HCard.from_html(changed_html)
+        hcard = Discovery::HCard.from_html(changed_html)
 
         expect(hcard.searchable).to eq(false)
       end
 
+      it "name is nil if empty" do
+        changed_html = html.sub(
+          "class=\"fn\">#{person.full_name}<",
+          "class=\"fn\"><"
+        ).sub(
+          "class=\"given_name\">#{person.first_name}<",
+          "class=\"given_name\"><"
+        ).sub(
+          "class=\"family_name\">#{person.last_name}<",
+          "class=\"family_name\"><"
+        )
+
+        hcard = Discovery::HCard.from_html(changed_html)
+
+        expect(hcard.full_name).to be_nil
+        expect(hcard.first_name).to be_nil
+        expect(hcard.last_name).to be_nil
+      end
+
       it "reads old-style HTML" do
         historic_html = <<-HTML
 <div id="content">
@@ -218,7 +236,7 @@ HTML
 </div>
 HTML
 
-        hcard = WebFinger::HCard.from_html(historic_html)
+        hcard = Discovery::HCard.from_html(historic_html)
         expect(hcard.url).to eq(person.url)
         expect(hcard.photo_large_url).to eq(photo_large_url)
         expect(hcard.photo_medium_url).to eq(photo_medium_url)
@@ -227,6 +245,9 @@ HTML
 
         expect(hcard.first_name).to eq(person.first_name)
         expect(hcard.last_name).to eq(person.last_name)
+
+        expect(hcard.guid).to be_nil
+        expect(hcard.public_key).to be_nil
       end
 
       it "fails if the document is incomplete" do
@@ -235,11 +256,11 @@ HTML
   <span class="fn">#{person.full_name}</span>
 </div>
 HTML
-        expect { WebFinger::HCard.from_html(invalid_html) }.to raise_error WebFinger::InvalidData
+        expect { Discovery::HCard.from_html(invalid_html) }.to raise_error Discovery::InvalidData
       end
 
       it "fails if the document is not HTML" do
-        expect { WebFinger::HCard.from_html("") }.to raise_error WebFinger::InvalidData
+        expect { Discovery::HCard.from_html("") }.to raise_error Discovery::InvalidData
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/web_finger/host_meta_spec.rb b/spec/lib/diaspora_federation/discovery/host_meta_spec.rb
similarity index 67%
rename from spec/lib/diaspora_federation/web_finger/host_meta_spec.rb
rename to spec/lib/diaspora_federation/discovery/host_meta_spec.rb
index 0bb9545..66e7fc8 100644
--- a/spec/lib/diaspora_federation/web_finger/host_meta_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/host_meta_spec.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  describe WebFinger::HostMeta do
+  describe Discovery::HostMeta do
     let(:base_url) { "https://pod.example.tld/" }
     let(:xml) {
       <<-XML
@@ -11,28 +11,33 @@ XML
     }
 
     it "must not create blank instances" do
-      expect { WebFinger::HostMeta.new }.to raise_error NoMethodError
+      expect { Discovery::HostMeta.new }.to raise_error NoMethodError
     end
 
     context "generation" do
       it "creates a nice XML document" do
-        hm = WebFinger::HostMeta.from_base_url(base_url)
+        hm = Discovery::HostMeta.from_base_url(base_url)
+        expect(hm.to_xml).to eq(xml)
+      end
+
+      it "converts object to string" do
+        hm = Discovery::HostMeta.from_base_url(URI(base_url))
         expect(hm.to_xml).to eq(xml)
       end
 
       it "appends a '/' if necessary" do
-        hm = WebFinger::HostMeta.from_base_url("https://pod.example.tld")
+        hm = Discovery::HostMeta.from_base_url("https://pod.example.tld")
         expect(hm.to_xml).to eq(xml)
       end
 
       it "fails if the base_url was omitted" do
-        expect { WebFinger::HostMeta.from_base_url("") }.to raise_error WebFinger::InvalidData
+        expect { Discovery::HostMeta.from_base_url("") }.to raise_error Discovery::InvalidData
       end
     end
 
     context "parsing" do
       it "parses its own output" do
-        hm = WebFinger::HostMeta.from_xml(xml)
+        hm = Discovery::HostMeta.from_xml(xml)
         expect(hm.webfinger_template_url).to eq("#{base_url}webfinger?q={uri}")
       end
 
@@ -49,7 +54,7 @@ XML
 
 </XRD>
 XML
-        hm = WebFinger::HostMeta.from_xml(historic_xml)
+        hm = Discovery::HostMeta.from_xml(historic_xml)
         expect(hm.webfinger_template_url).to eq("#{base_url}webfinger?q={uri}")
       end
 
@@ -59,7 +64,7 @@ XML
 <XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
 </XRD>
 XML
-        expect { WebFinger::HostMeta.from_xml(invalid_xml) }.to raise_error WebFinger::InvalidData
+        expect { Discovery::HostMeta.from_xml(invalid_xml) }.to raise_error Discovery::InvalidData
       end
 
       it "fails if the document contains a malformed webfinger url" do
@@ -69,11 +74,11 @@ XML
   <Link rel="lrdd" type="application/xrd+xml" template="#{base_url}webfinger?q="/>
 </XRD>
 XML
-        expect { WebFinger::HostMeta.from_xml(invalid_xml) }.to raise_error WebFinger::InvalidData
+        expect { Discovery::HostMeta.from_xml(invalid_xml) }.to raise_error Discovery::InvalidData
       end
 
       it "fails if the document is invalid" do
-        expect { WebFinger::HostMeta.from_xml("") }.to raise_error WebFinger::InvalidDocument
+        expect { Discovery::HostMeta.from_xml("") }.to raise_error Discovery::InvalidDocument
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/web_finger/web_finger_spec.rb b/spec/lib/diaspora_federation/discovery/web_finger_spec.rb
similarity index 60%
rename from spec/lib/diaspora_federation/web_finger/web_finger_spec.rb
rename to spec/lib/diaspora_federation/discovery/web_finger_spec.rb
index e5313b7..79d3e4f 100644
--- a/spec/lib/diaspora_federation/web_finger/web_finger_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/web_finger_spec.rb
@@ -1,9 +1,24 @@
 module DiasporaFederation
-  describe WebFinger::WebFinger do
+  describe Discovery::WebFinger do
     let(:person) { FactoryGirl.create(:person) }
-    let(:acct) { "acct:#{person.diaspora_handle}" }
+    let(:acct) { "acct:#{person.diaspora_id}" }
     let(:public_key_base64) { Base64.strict_encode64(person.serialized_public_key) }
 
+    let(:data) {
+      {
+        acct_uri:    "acct:#{person.diaspora_id}",
+        alias_url:   person.alias_url,
+        hcard_url:   person.hcard_url,
+        seed_url:    person.url,
+        profile_url: person.profile_url,
+        atom_url:    person.atom_url,
+        salmon_url:  person.salmon_url,
+        guid:        person.guid,
+        public_key:  person.serialized_public_key
+      }
+    }
+    let(:klass) { Discovery::WebFinger }
+
     let(:xml) {
       <<-XML
 <?xml version="1.0" encoding="UTF-8"?>
@@ -21,34 +36,18 @@ module DiasporaFederation
 XML
     }
 
-    it "must not create blank instances" do
-      expect { WebFinger::WebFinger.new({}) }.to raise_error ArgumentError
-    end
+    it_behaves_like "an Entity subclass"
 
     context "generation" do
       it "creates a nice XML document" do
-        wf = WebFinger::WebFinger.new(
-          acct_uri:    "acct:#{person.diaspora_handle}",
-          alias_url:   person.alias_url,
-          hcard_url:   person.hcard_url,
-          seed_url:    person.url,
-          profile_url: person.profile_url,
-          atom_url:    person.atom_url,
-          salmon_url:  person.salmon_url,
-          guid:        person.guid,
-          public_key:  person.serialized_public_key
-        )
+        wf = Discovery::WebFinger.new(data)
         expect(wf.to_xml).to eq(xml)
       end
-
-      it "fails if nil was given" do
-        expect { WebFinger::WebFinger.new(nil) }.to raise_error ArgumentError, "expected a Hash"
-      end
     end
 
     context "parsing" do
       it "reads its own output" do
-        wf = WebFinger::WebFinger.from_xml(xml)
+        wf = Discovery::WebFinger.from_xml(xml)
         expect(wf.acct_uri).to eq(acct)
         expect(wf.alias_url).to eq(person.alias_url)
         expect(wf.hcard_url).to eq(person.hcard_url)
@@ -62,7 +61,7 @@ XML
       end
 
       it "is frozen after parsing" do
-        wf = WebFinger::WebFinger.from_xml(xml)
+        wf = Discovery::WebFinger.from_xml(xml)
         expect(wf).to be_frozen
       end
 
@@ -84,7 +83,7 @@ XML
 </XRD>
 XML
 
-        wf = WebFinger::WebFinger.from_xml(historic_xml)
+        wf = Discovery::WebFinger.from_xml(historic_xml)
         expect(wf.acct_uri).to eq(acct)
         expect(wf.alias_url).to eq(person.alias_url)
         expect(wf.hcard_url).to eq(person.hcard_url)
@@ -97,17 +96,44 @@ XML
         expect(wf.public_key).to eq(person.serialized_public_key)
       end
 
+      it "reads future XML without guid and public key" do
+        future_xml = <<-XML
+<?xml version="1.0" encoding="UTF-8"?>
+<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
+  <Subject>#{acct}</Subject>
+  <Alias>#{person.alias_url}</Alias>
+  <Link rel="http://microformats.org/profile/hcard" type="text/html" href="#{person.hcard_url}"/>
+  <Link rel="http://joindiaspora.com/seed_location" type="text/html" href="#{person.url}"/>
+  <Link rel="http://webfinger.net/rel/profile-page" type="text/html" href="#{person.profile_url}"/>
+  <Link rel="http://schemas.google.com/g/2010#updates-from" type="application/atom+xml" href="#{person.atom_url}"/>
+  <Link rel="salmon" href="#{person.salmon_url}"/>
+</XRD>
+XML
+
+        wf = Discovery::WebFinger.from_xml(future_xml)
+        expect(wf.acct_uri).to eq(acct)
+        expect(wf.alias_url).to eq(person.alias_url)
+        expect(wf.hcard_url).to eq(person.hcard_url)
+        expect(wf.seed_url).to eq(person.url)
+        expect(wf.profile_url).to eq(person.profile_url)
+        expect(wf.atom_url).to eq(person.atom_url)
+        expect(wf.salmon_url).to eq(person.salmon_url)
+
+        expect(wf.guid).to be_nil
+        expect(wf.public_key).to be_nil
+      end
+
       it "fails if the document is empty" do
-        invalid_xml = <<XML
+        invalid_xml = <<-XML
 <?xml version="1.0" encoding="UTF-8"?>
 <XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
 </XRD>
 XML
-        expect { WebFinger::WebFinger.from_xml(invalid_xml) }.to raise_error WebFinger::InvalidData
+        expect { Discovery::WebFinger.from_xml(invalid_xml) }.to raise_error Discovery::InvalidData
       end
 
       it "fails if the document is not XML" do
-        expect { WebFinger::WebFinger.from_xml("") }.to raise_error WebFinger::InvalidDocument
+        expect { Discovery::WebFinger.from_xml("") }.to raise_error Discovery::InvalidDocument
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/web_finger/xrd_document_spec.rb b/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
similarity index 87%
rename from spec/lib/diaspora_federation/web_finger/xrd_document_spec.rb
rename to spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
index 18d566d..42ba34f 100644
--- a/spec/lib/diaspora_federation/web_finger/xrd_document_spec.rb
+++ b/spec/lib/diaspora_federation/discovery/xrd_document_spec.rb
@@ -1,5 +1,5 @@
 module DiasporaFederation
-  describe WebFinger::XrdDocument do
+  describe Discovery::XrdDocument do
     let(:xml) {
       <<XML
 <?xml version="1.0" encoding="UTF-8"?>
@@ -49,7 +49,7 @@ XML
 
     context "generation" do
       it "creates the xml document" do
-        doc = WebFinger::XrdDocument.new
+        doc = Discovery::XrdDocument.new
         doc.expires = data[:expires]
         doc.subject = data[:subject]
 
@@ -71,16 +71,16 @@ XML
 
     context "parsing" do
       it "reads the xml document" do
-        doc = WebFinger::XrdDocument.xml_data(xml)
+        doc = Discovery::XrdDocument.xml_data(xml)
         expect(doc).to eq(data)
       end
 
       it "raises InvalidDocument if the xml is empty" do
-        expect { WebFinger::XrdDocument.xml_data("") }.to raise_error WebFinger::InvalidDocument
+        expect { Discovery::XrdDocument.xml_data("") }.to raise_error Discovery::InvalidDocument
       end
 
       it "raises InvalidDocument if the xml is no XRD document" do
-        expect { WebFinger::XrdDocument.xml_data("<html></html>") }.to raise_error WebFinger::InvalidDocument
+        expect { Discovery::XrdDocument.xml_data("<html></html>") }.to raise_error Discovery::InvalidDocument
       end
     end
   end
diff --git a/spec/lib/diaspora_federation/entities/person_spec.rb b/spec/lib/diaspora_federation/entities/person_spec.rb
new file mode 100644
index 0000000..f4091ec
--- /dev/null
+++ b/spec/lib/diaspora_federation/entities/person_spec.rb
@@ -0,0 +1,8 @@
+module DiasporaFederation
+  describe Entities::Person do
+    let(:data) { FactoryGirl.attributes_for(:person_entity) }
+    let(:klass) { Entities::Person }
+
+    it_behaves_like "an Entity subclass"
+  end
+end
diff --git a/spec/lib/diaspora_federation/entities/profile_spec.rb b/spec/lib/diaspora_federation/entities/profile_spec.rb
new file mode 100644
index 0000000..398f601
--- /dev/null
+++ b/spec/lib/diaspora_federation/entities/profile_spec.rb
@@ -0,0 +1,8 @@
+module DiasporaFederation
+  describe Entities::Profile do
+    let(:data) { FactoryGirl.attributes_for(:profile_entity) }
+    let(:klass) { Entities::Profile }
+
+    it_behaves_like "an Entity subclass"
+  end
+end
diff --git a/spec/lib/diaspora_federation/entity_spec.rb b/spec/lib/diaspora_federation/entity_spec.rb
index 10192e5..085bfb1 100644
--- a/spec/lib/diaspora_federation/entity_spec.rb
+++ b/spec/lib/diaspora_federation/entity_spec.rb
@@ -18,19 +18,50 @@ module DiasporaFederation
         }.to raise_error ArgumentError, "missing required properties: test1, test2"
       end
 
-      it "sets the defaults" do
-        entity = Entities::TestDefaultEntity.new(test1: 1, test2: 2)
-        expect(entity.to_h[:test3]).to be_truthy
+      context "defaults" do
+        it "sets the defaults" do
+          entity = Entities::TestDefaultEntity.new(test1: "1", test2: "2")
+          expect(entity.test3).to be_truthy
+        end
+
+        it "handles callable defaults" do
+          entity = Entities::TestDefaultEntity.new(test1: "1", test2: "2")
+          expect(entity.test4).to be_truthy
+        end
+
+        it "uses provided values over defaults" do
+          entity = Entities::TestDefaultEntity.new(data)
+          expect(entity.test3).to be_falsey
+          expect(entity.test4).to be_falsey
+        end
       end
 
-      it "handles callable defaults" do
-        entity = Entities::TestDefaultEntity.new(test1: 1, test2: 2)
-        expect(entity.to_h[:test4]).to be_truthy
-      end
-
-      it "uses provided values over defaults" do
+      it "sets nil if string is empty" do
+        data[:test1] = ""
         entity = Entities::TestDefaultEntity.new(data)
-        expect(entity.to_h[:test3]).to be_falsey
+        expect(entity.test1).to be_nil
+      end
+
+      context "validation" do
+        let(:invalid_data) { {test1: "as;df", test2: nil, test3: "no boolean"} }
+
+        it "validates the entity and raise an error with failed properties if not valid" do
+          expect {
+            Entities::TestDefaultEntity.new(invalid_data)
+          }.to raise_error Entity::ValidationError, /Failed validation for properties:.*test1.*\|.*test2.*\|.*test3/
+        end
+
+        it "contains the failed rule" do
+          expect {
+            Entities::TestDefaultEntity.new(invalid_data)
+          }.to raise_error Entity::ValidationError, /property: test2, value: nil, rule: not_nil, with params: \{\}/
+        end
+
+        it "contains the params of the failed rule" do
+          expect {
+            Entities::TestDefaultEntity.new(invalid_data)
+          }.to raise_error Entity::ValidationError, /rule: regular_expression, with params: \{:regex=>.*\}/
+        end
       end
     end
 
@@ -54,7 +85,9 @@ module DiasporaFederation
 
       it "contains nodes for each of the properties" do
         entity = Entities::TestDefaultEntity.new(data)
-        entity.to_xml.children.each do |node|
+        xml_children = entity.to_xml.children
+        expect(xml_children).to have_exactly(4).items
+        xml_children.each do |node|
           expect(%w(test1 test2 test3 test4)).to include(node.name)
         end
       end
@@ -85,6 +118,7 @@ module DiasporaFederation
       it "gets xml-ified by #to_xml" do
         entity = Entities::TestNestedEntity.new(nested_data)
         xml = entity.to_xml
+        expect(xml.children).to have_exactly(4).items
         xml.children.each do |node|
           expect(%w(asdf test_entity other_entity)).to include(node.name)
         end
@@ -92,5 +126,23 @@ module DiasporaFederation
         expect(xml.xpath("other_entity")).to have_exactly(2).items
       end
     end
+
+    context "xml_name" do
+      let(:hash) { {test: "test", qwer: "qwer"} }
+
+      it "uses xml_name for the #to_xml" do
+        entity = Entities::TestEntityWithXmlName.new(hash)
+        xml_children = entity.to_xml.children
+        expect(xml_children).to have_exactly(2).items
+        xml_children.each do |node|
+          expect(%w(test asdf)).to include(node.name)
+        end
+      end
+
+      it "should not use the xml_name for the #to_h" do
+        entity = Entities::TestEntityWithXmlName.new(hash)
+        expect(entity.to_h).to eq(hash)
+      end
+    end
   end
 end
diff --git a/spec/lib/diaspora_federation/fetcher_spec.rb b/spec/lib/diaspora_federation/fetcher_spec.rb
new file mode 100644
index 0000000..a84d819
--- /dev/null
+++ b/spec/lib/diaspora_federation/fetcher_spec.rb
@@ -0,0 +1,56 @@
+module DiasporaFederation
+  describe Fetcher do
+    describe ".get" do
+      it "gets the url" do
+        stub_request(:get, "http://www.example.com")
+          .to_return(body: "foobar", status: 200)
+
+        response = Fetcher.get("http://www.example.com")
+        expect(response.body).to eq("foobar")
+      end
+
+      it "follows redirects" do
+        stub_request(:get, "http://www.example.com")
+          .to_return(status: 302, headers: {"Location" => "http://www.example.com/redirected"})
+        stub_request(:get, "http://www.example.com/redirected")
+          .to_return(body: "foobar", status: 200)
+
+        response = Fetcher.get("http://www.example.com")
+        expect(response.body).to eq("foobar")
+      end
+
+      it "follows redirects 4 times" do
+        stub_request(:get, "http://www.example.com")
+          .to_return(status: 302, headers: {"Location" => "http://www.example.com"}).times(4)
+          .to_return(status: 200)
+
+        Fetcher.get("http://www.example.com")
+      end
+
+      it "follows redirects not more than 4 times" do
+        stub_request(:get, "http://www.example.com")
+          .to_return(status: 302, headers: {"Location" => "http://www.example.com"})
+
+        expect { Fetcher.get("http://www.example.com") }.to raise_error FaradayMiddleware::RedirectLimitReached
+      end
+
+      it "uses the gem name as User-Agent" do
+        stub_request(:get, "http://www.example.com")
+          .with(headers: {"User-Agent" => "DiasporaFederation/#{DiasporaFederation::VERSION}"})
+
+        Fetcher.get("http://www.example.com")
+      end
+    end
+
+    describe ".connection" do
+      it "returns a new connection every time" do
+        expect(Fetcher.connection).to be_a Faraday::Connection
+      end
+
+      it "returns a new connection every time" do
+        connection1 = Fetcher.connection
+        expect(Fetcher.connection).to_not be(connection1)
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/properties_dsl_spec.rb b/spec/lib/diaspora_federation/properties_dsl_spec.rb
index 8a225f2..cd8a287 100644
--- a/spec/lib/diaspora_federation/properties_dsl_spec.rb
+++ b/spec/lib/diaspora_federation/properties_dsl_spec.rb
@@ -8,19 +8,12 @@ module DiasporaFederation
         properties = dsl.class_props
         expect(properties).to have(1).item
         expect(properties.first[:name]).to eq(:test)
-        expect(properties.first[:type]).to eq(String)
-      end
-
-      it "can name simple properties by string" do
-        dsl.property "test"
-        properties = dsl.class_props
-        expect(properties).to have(1).item
-        expect(properties.first[:name]).to eq("test")
+        expect(properties.first[:xml_name]).to eq(:test)
         expect(properties.first[:type]).to eq(String)
       end
 
       it "will not accept other types for names" do
-        [1234, true, {}].each do |val|
+        ["test", 1234, true, {}].each do |val|
           expect {
             dsl.property val
           }.to raise_error PropertiesDSL::InvalidName
@@ -34,8 +27,26 @@ module DiasporaFederation
         properties = dsl.class_props
         expect(properties).to have(3).items
         expect(properties.map {|e| e[:name] }).to include(:test, :asdf, :zzzz)
+        expect(properties.map {|e| e[:xml_name] }).to include(:test, :asdf, :zzzz)
         properties.each {|e| expect(e[:type]).to eq(String) }
       end
+
+      it "can add an xml name to simple properties with a symbol" do
+        dsl.property :test, xml_name: :xml_test
+        properties = dsl.class_props
+        expect(properties).to have(1).item
+        expect(properties.first[:name]).to eq(:test)
+        expect(properties.first[:xml_name]).to eq(:xml_test)
+        expect(properties.first[:type]).to eq(String)
+      end
+
+      it "will not accept other types for xml names" do
+        ["test", 1234, true, {}].each do |val|
+          expect {
+            dsl.property :test, xml_name: val
+          }.to raise_error PropertiesDSL::InvalidName, "invalid xml_name"
+        end
+      end
     end
 
     context "nested entities" do
@@ -75,6 +86,12 @@ module DiasporaFederation
           }.to raise_error PropertiesDSL::InvalidType
         end
       end
+
+      it "can not add an xml name to a nested entity" do
+        expect {
+          dsl.entity :other, Entities::TestEntity, xml_name: :other_name
+        }.to raise_error ArgumentError, "xml_name is not supported for nested entities"
+      end
     end
 
     describe ".default_values" do
diff --git a/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb b/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb
new file mode 100644
index 0000000..a23887b
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/h_card_validator_spec.rb
@@ -0,0 +1,55 @@
+module DiasporaFederation
+  describe Validators::HCardValidator do
+    let(:entity) { :h_card }
+
+    def hcard_stub(data={})
+      OpenStruct.new(FactoryGirl.attributes_for(:h_card).merge(data))
+    end
+
+    it "validates a well-formed instance" do
+      validator = Validators::HCardValidator.new(hcard_stub)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    describe "#full_name" do
+      it_behaves_like "a name validator" do
+        let(:property) { :full_name }
+        let(:length) { 70 }
+      end
+    end
+
+    %i(first_name last_name).each do |prop|
+      describe "##{prop}" do
+        it_behaves_like "a name validator" do
+          let(:property) { prop }
+          let(:length) { 32 }
+        end
+      end
+    end
+
+    %i(photo_large_url photo_medium_url photo_small_url).each do |prop|
+      describe "##{prop}" do
+        it "must not be nil or empty" do
+          [nil, ""].each do |val|
+            validator = Validators::HCardValidator.new(hcard_stub(prop => val))
+
+            expect(validator).not_to be_valid
+            expect(validator.errors).to include(prop)
+          end
+        end
+
+        it_behaves_like "a url path validator" do
+          let(:property) { prop }
+        end
+      end
+    end
+
+    describe "#searchable" do
+      it_behaves_like "a boolean validator" do
+        let(:property) { :searchable }
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/person_validator_spec.rb b/spec/lib/diaspora_federation/validators/person_validator_spec.rb
new file mode 100644
index 0000000..4f62ce0
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/person_validator_spec.rb
@@ -0,0 +1,41 @@
+module DiasporaFederation
+  describe Validators::PersonValidator do
+    let(:entity) { :person_entity }
+
+    it "validates a well-formed instance" do
+      instance = OpenStruct.new(FactoryGirl.attributes_for(:person_entity))
+      validator = Validators::PersonValidator.new(instance)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it_behaves_like "a diaspora id validator" do
+      let(:property) { :diaspora_id }
+    end
+
+    it_behaves_like "a guid validator" do
+      let(:property) { :guid }
+    end
+
+    context "#url" do
+      it_behaves_like "a url validator without path" do
+        let(:property) { :url }
+      end
+    end
+
+    context "#profile" do
+      it "fails if profile is nil" do
+        instance = OpenStruct.new(FactoryGirl.attributes_for(:person_entity, profile: nil))
+        validator = Validators::PersonValidator.new(instance)
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:profile)
+      end
+    end
+
+    it_behaves_like "a public key validator" do
+      let(:property) { :exported_key }
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/profile_validator_spec.rb b/spec/lib/diaspora_federation/validators/profile_validator_spec.rb
new file mode 100644
index 0000000..9f50174
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/profile_validator_spec.rb
@@ -0,0 +1,112 @@
+module DiasporaFederation
+  describe Validators::ProfileValidator do
+    let(:entity) { :profile_entity }
+
+    def profile_stub(data={})
+      OpenStruct.new(FactoryGirl.attributes_for(:profile_entity).merge(data))
+    end
+
+    it "validates a well-formed instance" do
+      validator = Validators::ProfileValidator.new(profile_stub)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it_behaves_like "a diaspora id validator" do
+      let(:property) { :diaspora_id }
+    end
+
+    %i(first_name last_name).each do |prop|
+      describe "##{prop}" do
+        it_behaves_like "a name validator" do
+          let(:property) { prop }
+          let(:length) { 32 }
+        end
+      end
+    end
+
+    %i(image_url image_url_medium image_url_small).each do |prop|
+      describe "##{prop}" do
+        it "is allowed to be nil" do
+          validator = Validators::ProfileValidator.new(profile_stub(prop => nil))
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+
+        it_behaves_like "a url path validator" do
+          let(:property) { prop }
+        end
+      end
+    end
+
+    describe "#gender" do
+      it_behaves_like "a length validator" do
+        let(:property) { :gender }
+        let(:length) { 255 }
+      end
+    end
+
+    describe "#bio" do
+      it_behaves_like "a length validator" do
+        let(:property) { :bio }
+        let(:length) { 65_535 }
+      end
+    end
+
+    describe "#location" do
+      it_behaves_like "a length validator" do
+        let(:property) { :location }
+        let(:length) { 255 }
+      end
+    end
+
+    describe "#birthday" do
+      it "may be empty or nil" do
+        [nil, ""].each do |val|
+          validator = Validators::ProfileValidator.new(profile_stub(birthday: val))
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+      end
+
+      it "may be a Date or date string" do
+        [Date.parse("2013-06-29"), "2013-06-29"].each do |val|
+          validator = Validators::ProfileValidator.new(profile_stub(birthday: val))
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+      end
+
+      it "must not be an arbitrary string or other object" do
+        ["asdf asdf", true, 1234].each do |val|
+          validator = Validators::ProfileValidator.new(profile_stub(birthday: val))
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:birthday)
+        end
+      end
+    end
+
+    %i(searchable nsfw).each do |prop|
+      describe "##{prop}" do
+        it_behaves_like "a boolean validator" do
+          let(:property) { prop }
+        end
+      end
+    end
+
+    describe "#tag_string" do
+      it "must not contain more than 5 tags" do
+        validator = Validators::ProfileValidator.new(
+          profile_stub(tag_string: "#i #have #too #many #tags #in #my #profile"))
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:tag_string)
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb b/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
new file mode 100644
index 0000000..6a65a6b
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
@@ -0,0 +1,54 @@
+describe Validation::Rule::Birthday do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:birthday, birthday: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:birthday)
+  end
+
+  context "validation" do
+    it "validates a date object" do
+      validator = Validation::Validator.new(OpenStruct.new(birthday: Date.new))
+      validator.rule(:birthday, :birthday)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a string" do
+      validator = Validation::Validator.new(OpenStruct.new(birthday: "2015-07-19"))
+      validator.rule(:birthday, :birthday)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates an empty string" do
+      validator = Validation::Validator.new(OpenStruct.new(birthday: ""))
+      validator.rule(:birthday, :birthday)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates nil" do
+      validator = Validation::Validator.new(OpenStruct.new(birthday: nil))
+      validator.rule(:birthday, :birthday)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails for invalid date string" do
+      validator = Validation::Validator.new(OpenStruct.new(birthday: "i'm no date"))
+      validator.rule(:birthday, :birthday)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:birthday)
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
new file mode 100644
index 0000000..74dc2e5
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
@@ -0,0 +1,74 @@
+describe Validation::Rule::Boolean do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:number, numeric: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:boolean)
+  end
+
+  context "validation" do
+    context "strings" do
+      it "validates boolean-esque strings" do
+        %w(true false yes no t f y n 1 0).each do |str|
+          validator = Validation::Validator.new(OpenStruct.new(boolean: str))
+          validator.rule(:boolean, :boolean)
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+      end
+
+      it "fails for non-boolean-esque strings" do
+        validator = Validation::Validator.new(OpenStruct.new(boolean: "asdf"))
+        validator.rule(:boolean, :boolean)
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:boolean)
+      end
+    end
+
+    context "numbers" do
+      it "validates 0 and 1 to boolean" do
+        [0, 1].each do |num|
+          validator = Validation::Validator.new(OpenStruct.new(boolean: num))
+          validator.rule(:boolean, :boolean)
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+      end
+
+      it "fails for all other numbers" do
+        validator = Validation::Validator.new(OpenStruct.new(boolean: 1234))
+        validator.rule(:boolean, :boolean)
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:boolean)
+      end
+    end
+
+    context "boolean types" do
+      it "validates true and false" do
+        [true, false].each do |bln|
+          validator = Validation::Validator.new(OpenStruct.new(boolean: bln))
+          validator.rule(:boolean, :boolean)
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+      end
+    end
+
+    it "fails for nil" do
+      validator = Validation::Validator.new(OpenStruct.new(boolean: nil))
+      validator.rule(:boolean, :boolean)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:boolean)
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
new file mode 100644
index 0000000..072004e
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
@@ -0,0 +1,78 @@
+describe Validation::Rule::DiasporaId do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:diaspora_id, diaspora_id: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:diaspora_id)
+  end
+
+  context "validation" do
+    it "validates a normal diaspora id" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@example.com"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a diaspora id with localhost" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@localhost"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a diaspora id with port" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@example.com:3000"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a diaspora id with IPv4 address" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@123.45.67.89"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a diaspora id with IPv6 address" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@[2001:1234:5678:90ab:cdef::1]"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a diaspora id with . and -" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some-fancy.user@example.com"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails if the diaspora id contains a / in the domain-name" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user@example.com/friendica"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:diaspora_id)
+    end
+
+    it "fails if the diaspora id contains a special-chars in the username" do
+      validator = Validation::Validator.new(OpenStruct.new(diaspora_id: "some_user$^%@example.com"))
+      validator.rule(:diaspora_id, :diaspora_id)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:diaspora_id)
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
new file mode 100644
index 0000000..272adfb
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
@@ -0,0 +1,63 @@
+describe Validation::Rule::Guid do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:guid, guid: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:guid)
+  end
+
+  context "validation" do
+    it "validates a string at least 16 chars long, consisting of [0-9a-f] (diaspora)" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: "abcdef0123456789"))
+      validator.rule(:guid, :guid)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a long string with random characters and [-_@.:] (redmatrix)" do
+      validator = Validation::Validator.new(
+        OpenStruct.new(guid: "1234567890ABCDefgh_ijkl-mnopqrSTUVwxyz@example.com:3000"))
+      validator.rule(:guid, :guid)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails if the string is too short" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: "012345"))
+      validator.rule(:guid, :guid)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:guid)
+    end
+
+    it "fails if the string contains invalid chars" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: "ghijklmnopqrstuvwxyz++"))
+      validator.rule(:guid, :guid)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:guid)
+    end
+
+    it "fails if the string is empty" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: ""))
+      validator.rule(:guid, :guid)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:guid)
+    end
+
+    it "fails if the string is nil" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: nil))
+      validator.rule(:guid, :guid)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:guid)
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/nilable_uri_spec.rb b/spec/lib/diaspora_federation/validators/rules/nilable_uri_spec.rb
new file mode 100644
index 0000000..691e4fd
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/nilable_uri_spec.rb
@@ -0,0 +1,57 @@
+describe Validation::Rule::NilableURI do
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:nilableURI)
+  end
+
+  context "validation" do
+    it "validates a valid uri" do
+      validator = Validation::Validator.new(OpenStruct.new(uri: "http://example.com"))
+      validator.rule(:uri, :nilableURI)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates nil" do
+      validator = Validation::Validator.new(OpenStruct.new(uri: nil))
+      validator.rule(:uri, :nilableURI)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails when given an invalid uri" do
+      validator = Validation::Validator.new(OpenStruct.new(uri: "foo:/%urim"))
+      validator.rule(:uri, :nilableURI)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:uri)
+    end
+
+    context "part validation" do
+      it "fails to validate when given a uri without a host" do
+        validator = Validation::Validator.new(OpenStruct.new(uri: "http:foo@"))
+        validator.rule(:uri, :nilableURI)
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:uri)
+      end
+
+      it "fails to validate when given a uri without a scheme" do
+        validator = Validation::Validator.new(OpenStruct.new(uri: "example.com"))
+        validator.rule(:uri, :nilableURI)
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:uri)
+      end
+
+      it "fails to validate when given a uri without a path" do
+        validator = Validation::Validator.new(OpenStruct.new(uri: "http://example.com"))
+        validator.rule(:uri, nilableURI: %i(host path))
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:uri)
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
new file mode 100644
index 0000000..ae5d1e6
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
@@ -0,0 +1,38 @@
+describe Validation::Rule::NotNil do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:not_nil, not_nil: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:not_nil)
+  end
+
+  context "validation" do
+    it "validates a string " do
+      validator = Validation::Validator.new(OpenStruct.new(not_nil: "abcd"))
+      validator.rule(:not_nil, :not_nil)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates a object " do
+      validator = Validation::Validator.new(OpenStruct.new(not_nil: Object.new))
+      validator.rule(:not_nil, :not_nil)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails if it is nil" do
+      validator = Validation::Validator.new(OpenStruct.new(not_nil: nil))
+      validator.rule(:not_nil, :not_nil)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:not_nil)
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
new file mode 100644
index 0000000..f4eb9ca
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
@@ -0,0 +1,71 @@
+describe Validation::Rule::PublicKey do
+  it "will not accept parameters" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:key, public_key: {param: true})
+    }.to raise_error ArgumentError
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:public_key)
+  end
+
+  context "validation" do
+    ["PUBLIC KEY", "RSA PUBLIC KEY"].each do |key_type|
+      context key_type do
+        let(:prefix) { "-----BEGIN #{key_type}-----" }
+        let(:suffix) { "-----END #{key_type}-----" }
+
+        let(:key) { "#{prefix}\nAAAAAA==\n#{suffix}\n" }
+
+        it "validates an exported RSA key" do
+          validator = Validation::Validator.new(OpenStruct.new(key: key))
+          validator.rule(:key, :public_key)
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+
+        it "strips whitespace" do
+          validator = Validation::Validator.new(OpenStruct.new(key: "  \n   #{key}\n \n  "))
+          validator.rule(:key, :public_key)
+
+          expect(validator).to be_valid
+          expect(validator.errors).to be_empty
+        end
+
+        it "fails if the prefix is missing" do
+          validator = Validation::Validator.new(OpenStruct.new(key: "\nAAAAAA==\n#{suffix}\n"))
+          validator.rule(:key, :public_key)
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:key)
+        end
+
+        it "fails if the suffix is missing" do
+          validator = Validation::Validator.new(OpenStruct.new(key: "#{prefix}\nAAAAAA==\n\n"))
+          validator.rule(:key, :public_key)
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:key)
+        end
+
+        it "fails if the key is empty" do
+          validator = Validation::Validator.new(OpenStruct.new(key: ""))
+          validator.rule(:key, :public_key)
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:key)
+        end
+
+        it "fails if the key is nil" do
+          validator = Validation::Validator.new(OpenStruct.new(key: nil))
+          validator.rule(:key, :public_key)
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:key)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
new file mode 100644
index 0000000..a54e846
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
@@ -0,0 +1,57 @@
+describe Validation::Rule::TagCount do
+  it "requires a parameter" do
+    validator = Validation::Validator.new({})
+    expect {
+      validator.rule(:tags, :tag_count)
+    }.to raise_error ArgumentError
+  end
+
+  it "requires a integer as parameter" do
+    validator = Validation::Validator.new({})
+    [nil, "", 5.5].each do |val|
+      expect {
+        validator.rule(:tags, tag_count: {maximum: val})
+      }.to raise_error ArgumentError, "A number has to be specified for :maximum"
+    end
+  end
+
+  it "has an error key" do
+    expect(described_class.new(maximum: 5).error_key).to eq(:tag_count)
+  end
+
+  context "validation" do
+    let(:tag_str) { "#i #love #tags" }
+
+    it "validates less tags" do
+      validator = Validation::Validator.new(OpenStruct.new(tags: tag_str))
+      validator.rule(:tags, tag_count: {maximum: 5})
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "validates exactly as many tags" do
+      validator = Validation::Validator.new(OpenStruct.new(tags: tag_str))
+      validator.rule(:tags, tag_count: {maximum: 3})
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    it "fails for too many tags" do
+      validator = Validation::Validator.new(OpenStruct.new(tags: tag_str))
+      validator.rule(:tags, tag_count: {maximum: 1})
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:tags)
+    end
+
+    it "validates if tags are nil" do
+      validator = Validation::Validator.new(OpenStruct.new(tags: nil))
+      validator.rule(:tags, tag_count: {maximum: 5})
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
new file mode 100644
index 0000000..b9813c0
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/web_finger_validator_spec.rb
@@ -0,0 +1,45 @@
+module DiasporaFederation
+  describe Validators::WebFingerValidator do
+    let(:entity) { :webfinger }
+
+    def webfinger_stub(data={})
+      OpenStruct.new(FactoryGirl.attributes_for(:webfinger).merge(data))
+    end
+
+    it "validates a well-formed instance" do
+      validator = Validators::WebFingerValidator.new(webfinger_stub)
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+
+    describe "#acct_uri" do
+      it "fails if it is nil or empty" do
+        [nil, ""].each do |val|
+          validator = Validators::WebFingerValidator.new(webfinger_stub(acct_uri: val))
+
+          expect(validator).not_to be_valid
+          expect(validator.errors).to include(:acct_uri)
+        end
+      end
+    end
+
+    %i(alias_url hcard_url profile_url atom_url salmon_url).each do |prop|
+      describe "##{prop}" do
+        it_behaves_like "a url validator without path"  do
+          let(:property) { prop }
+        end
+
+        it_behaves_like "a url path validator" do
+          let(:property) { prop }
+        end
+      end
+    end
+
+    describe "#seed_url" do
+      it_behaves_like "a url validator without path" do
+        let(:property) { :seed_url }
+      end
+    end
+  end
+end
diff --git a/spec/lib/diaspora_federation_spec.rb b/spec/lib/diaspora_federation_spec.rb
index 72434c5..c875582 100644
--- a/spec/lib/diaspora_federation_spec.rb
+++ b/spec/lib/diaspora_federation_spec.rb
@@ -6,14 +6,31 @@ module DiasporaFederation
         DiasporaFederation.validate_config
       end
 
-      it "should fails if the server_uri is missing" do
+      it "should fail if the server_uri is missing" do
         temp = DiasporaFederation.server_uri
         DiasporaFederation.server_uri = nil
-        expect { DiasporaFederation.validate_config }.to raise_error ConfigurationError, "Missing server_uri"
+        expect { DiasporaFederation.validate_config }.to raise_error ConfigurationError,
+                                                                     "server_uri: Missing or invalid"
         DiasporaFederation.server_uri = temp
       end
 
-      it "should validate the config" do
+      it "should fail if the certificate_authorities is missing" do
+        temp = DiasporaFederation.certificate_authorities
+        DiasporaFederation.certificate_authorities = nil
+        expect { DiasporaFederation.validate_config }.to raise_error ConfigurationError,
+                                                                     "certificate_authorities: Not configured"
+        DiasporaFederation.certificate_authorities = temp
+      end
+
+      it "should fail if the certificate_authorities is missing" do
+        temp = DiasporaFederation.certificate_authorities
+        DiasporaFederation.certificate_authorities = "/unknown"
+        expect { DiasporaFederation.validate_config }.to raise_error ConfigurationError,
+                                                                     "certificate_authorities: File not found: /unknown"
+        DiasporaFederation.certificate_authorities = temp
+      end
+
+      it "should validate the callbacks" do
         expect(DiasporaFederation.callbacks).to receive(:definition_complete?).and_return(false)
         expect { DiasporaFederation.validate_config }.to raise_error ConfigurationError, "Missing handlers for "
       end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index b3e6ca4..ceb42ca 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -6,6 +6,7 @@ unless ENV["NO_COVERAGE"] == "true"
     SimpleCov::Formatter::RcovFormatter
   ]
   SimpleCov.start do
+    add_filter "lib/diaspora_federation/logging.rb"
     add_filter "spec"
     add_filter "test"
   end
@@ -18,6 +19,7 @@ ENV["RAILS_ENV"] ||= "test"
 require File.join(File.dirname(__FILE__), "..", "test", "dummy", "config", "environment")
 
 require "rspec/rails"
+require "webmock/rspec"
 
 # load factory girl factories
 require "factories"
@@ -28,12 +30,9 @@ require "entities"
 # some helper methods
 
 def alice
-  @alice ||= Person.find_by(diaspora_handle: "alice@localhost:3000")
+  @alice ||= Person.find_by(diaspora_id: "alice@localhost:3000")
 end
 
-# Force fixture rebuild
-FileUtils.rm_f(Rails.root.join("tmp", "fixture_builder.yml"))
-
 # Requires supporting files with custom matchers and macros, etc,
 # in ./support/ and its subdirectories.
 fixture_builder_file = "#{File.dirname(__FILE__)}/support/fixture_builder.rb"
@@ -53,6 +52,10 @@ RSpec.configure do |config|
   config.include FactoryGirl::Syntax::Methods
   config.use_transactional_fixtures = true
 
+  # load fixtures
+  config.fixture_path = "#{::Rails.root}/test/fixtures"
+  config.global_fixtures = :all
+
   config.mock_with :rspec do |mocks|
     # Prevents you from mocking or stubbing a method that does not exist on
     # a real object. This is generally recommended, and will default to
diff --git a/spec/support/fixture_builder.rb b/spec/support/fixture_builder.rb
index dbb7f41..a737a58 100644
--- a/spec/support/fixture_builder.rb
+++ b/spec/support/fixture_builder.rb
@@ -11,6 +11,6 @@ FixtureBuilder.configure do |fbuilder|
 
   # now declare objects
   fbuilder.factory do
-    FactoryGirl.create(:person, diaspora_handle: "alice@localhost:3000")
+    FactoryGirl.create(:person, diaspora_id: "alice@localhost:3000")
   end
 end
diff --git a/spec/support/fixture_generation.rb b/spec/support/fixture_generation.rb
index d7081e7..e06dec1 100644
--- a/spec/support/fixture_generation.rb
+++ b/spec/support/fixture_generation.rb
@@ -9,6 +9,12 @@ module FixtureGeneration
       file.puts(markup)
     end
   end
+
+  def self.load_fixture(name, fixture_path=nil)
+    fixture_path = Rails.root.join("tmp", "fixtures") unless fixture_path
+    fixture_file = fixture_path.join("#{name}.fixture.html")
+    File.open(fixture_file).read
+  end
 end
 
 RSpec::Rails::ControllerExampleGroup.class_eval do
diff --git a/spec/support/shared_entity_specs.rb b/spec/support/shared_entity_specs.rb
new file mode 100644
index 0000000..8946cee
--- /dev/null
+++ b/spec/support/shared_entity_specs.rb
@@ -0,0 +1,33 @@
+shared_examples "an Entity subclass" do
+  it "should be an Entity" do
+    expect(klass).to be < DiasporaFederation::Entity
+  end
+
+  it "has its properties set" do
+    expect(klass.class_prop_names).to include(*data.keys)
+  end
+
+  context "behaviour" do
+    let(:instance) { klass.new(data) }
+
+    describe "initialize" do
+      it "must not create blank instances" do
+        expect { klass.new({}) }.to raise_error ArgumentError
+      end
+
+      it "fails if nil was given" do
+        expect { klass.new(nil) }.to raise_error ArgumentError, "expected a Hash"
+      end
+
+      it "should be frozen" do
+        expect(instance).to be_frozen
+      end
+    end
+
+    describe "#to_h" do
+      it "should resemble the input data" do
+        expect(instance.to_h).to eq(data)
+      end
+    end
+  end
+end
diff --git a/spec/support/shared_validator_specs.rb b/spec/support/shared_validator_specs.rb
new file mode 100644
index 0000000..74a12da
--- /dev/null
+++ b/spec/support/shared_validator_specs.rb
@@ -0,0 +1,211 @@
+def entity_stub(entity, property, val)
+  instance = OpenStruct.new(FactoryGirl.attributes_for(entity))
+  instance.public_send("#{property}=", val)
+  instance
+end
+
+ALPHANUMERIC_RANGE = [*"0".."9", *"A".."Z", *"a".."z"]
+
+def alphanumeric_string(length)
+  Array.new(length) { ALPHANUMERIC_RANGE.sample }.join
+end
+
+shared_examples "a diaspora id validator" do
+  it "must not be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(property)
+    end
+  end
+
+  it "must be a valid diaspora id" do
+    validator = described_class.new(entity_stub(entity, property, "i am a weird diaspora id @@@ ### 12345"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+end
+
+shared_examples "a guid validator" do
+  it "validates a well-formed guid from redmatrix" do
+    validator = described_class.new(entity_stub(entity, property, "1234567890ABCDefgh_ijkl-mnopQR@example.com:3000"))
+
+    expect(validator).to be_valid
+    expect(validator.errors).to be_empty
+  end
+
+  it "must be at least 16 chars" do
+    validator = described_class.new(entity_stub(entity, property, "aaaaaa"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "must only contain [0-9a-z-_@.:]" do
+    validator = described_class.new(entity_stub(entity, property, "zzz+-#*$$"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "must not be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(property)
+    end
+  end
+end
+
+shared_examples "a boolean validator" do
+  it "validates a well-formed boolean" do
+    [true, "true", false, "false"].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+  end
+
+  it "must not be an arbitrary string or other object" do
+    ["asdf", Time.zone.today, 1234].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(property)
+    end
+  end
+end
+
+shared_examples "a public key validator" do
+  it "fails for malformed rsa key" do
+    validator = described_class.new(entity_stub(entity, property, "ASDF"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "must not be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(property)
+    end
+  end
+end
+
+shared_examples "a name validator" do
+  it "is allowed to be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+  end
+
+  it "is allowed to contain special chars" do
+    validator = described_class.new(entity_stub(entity, property, "cool name ©"))
+
+    expect(validator).to be_valid
+    expect(validator.errors).to be_empty
+  end
+
+  it "validates the maximum number of chars" do
+    validator = described_class.new(entity_stub(entity, property, alphanumeric_string(length)))
+
+    expect(validator).to be_valid
+    expect(validator.errors).to be_empty
+  end
+
+  it "must not exceed the maximum number of chars" do
+    validator = described_class.new(entity_stub(entity, property, alphanumeric_string(length + 1)))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "must not contain semicolons" do
+    validator = described_class.new(entity_stub(entity, property, "asdf;qwer;yxcv"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+end
+
+shared_examples "a length validator" do
+  it "is allowed to be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).to be_valid
+      expect(validator.errors).to be_empty
+    end
+  end
+
+  it "is allowed to contain special chars" do
+    validator = described_class.new(entity_stub(entity, property, "cool name ©;:#%"))
+
+    expect(validator).to be_valid
+    expect(validator.errors).to be_empty
+  end
+
+  it "validates the maximum number of chars" do
+    validator = described_class.new(entity_stub(entity, property, alphanumeric_string(length)))
+
+    expect(validator).to be_valid
+    expect(validator.errors).to be_empty
+  end
+
+  it "must not exceed the maximum number of chars" do
+    validator = described_class.new(entity_stub(entity, property, alphanumeric_string(length + 1)))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+end
+
+shared_examples "a url validator without path" do
+  it "must not be nil or empty" do
+    [nil, ""].each do |val|
+      validator = described_class.new(entity_stub(entity, property, val))
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(property)
+    end
+  end
+
+  it "fails for url with special chars" do
+    validator = described_class.new(entity_stub(entity, property, "https://asdf$%.com"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "fails for url without scheme" do
+    validator = described_class.new(entity_stub(entity, property, "example.com"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+end
+
+shared_examples "a url path validator" do
+  it "fails for url with special chars" do
+    validator = described_class.new(entity_stub(entity, property, "https://asdf$%.com/some/path"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+
+  it "fails for url without path" do
+    validator = described_class.new(entity_stub(entity, property, "https://example.com"))
+
+    expect(validator).not_to be_valid
+    expect(validator.errors).to include(property)
+  end
+end
diff --git a/test/dummy/app/models/person.rb b/test/dummy/app/models/person.rb
index a46a163..4fce4cd 100644
--- a/test/dummy/app/models/person.rb
+++ b/test/dummy/app/models/person.rb
@@ -7,7 +7,7 @@ class Person < ActiveRecord::Base
   def atom_url;    "#{url}public/#{nickname}.atom" end
   def salmon_url;  "#{url}receive/users/#{guid}" end
 
-  def nickname;         diaspora_handle.split("@")[0] end
+  def nickname;         diaspora_id.split("@")[0] end
 
   def photo_default_url;  "#{url}assets/user/default.png" end
 
diff --git a/test/dummy/config/initializers/diaspora_federation.rb b/test/dummy/config/initializers/diaspora_federation.rb
index a41a7c5..d7883f1 100644
--- a/test/dummy/config/initializers/diaspora_federation.rb
+++ b/test/dummy/config/initializers/diaspora_federation.rb
@@ -1,16 +1,26 @@
-require "diaspora_federation/web_finger"
+require "diaspora_federation/discovery"
+
+if File.file?("/etc/ssl/certs/ca-certificates.crt")
+  # For Debian, Ubuntu, Archlinux, Gentoo
+  ca_file = "/etc/ssl/certs/ca-certificates.crt"
+else
+  # For CentOS, Fedora
+  ca_file = "/etc/pki/tls/certs/ca-bundle.crt"
+end
 
 # configure the federation engine
 DiasporaFederation.configure do |config|
   # the pod url
   config.server_uri = URI("http://localhost:3000/")
 
+  config.certificate_authorities = ca_file
+
   config.define_callbacks do
-    on :person_webfinger_fetch do |handle|
-      person = Person.find_by(diaspora_handle: handle)
+    on :person_webfinger_fetch do |diaspora_id|
+      person = Person.find_by(diaspora_id: diaspora_id)
       if person
-        DiasporaFederation::WebFinger::WebFinger.new(
-          acct_uri:    "acct:#{person.diaspora_handle}",
+        DiasporaFederation::Discovery::WebFinger.new(
+          acct_uri:    "acct:#{person.diaspora_id}",
           alias_url:   person.alias_url,
           hcard_url:   person.hcard_url,
           seed_url:    person.url,
@@ -26,7 +36,7 @@ DiasporaFederation.configure do |config|
     on :person_hcard_fetch do |guid|
       person = Person.find_by(guid: guid)
       if person
-        DiasporaFederation::WebFinger::HCard.new(
+        DiasporaFederation::Discovery::HCard.new(
           guid:             person.guid,
           nickname:         person.nickname,
           full_name:        person.full_name,
diff --git a/test/dummy/db/migrate/20150722224751_rename_diaspora_handle_to_diaspora_id.rb b/test/dummy/db/migrate/20150722224751_rename_diaspora_handle_to_diaspora_id.rb
new file mode 100644
index 0000000..e997558
--- /dev/null
+++ b/test/dummy/db/migrate/20150722224751_rename_diaspora_handle_to_diaspora_id.rb
@@ -0,0 +1,5 @@
+class RenameDiasporaHandleToDiasporaId < ActiveRecord::Migration
+  def change
+    rename_column :people, :diaspora_handle, :diaspora_id
+  end
+end
diff --git a/test/dummy/db/schema.rb b/test/dummy/db/schema.rb
index 7167574..dfcda3a 100644
--- a/test/dummy/db/schema.rb
+++ b/test/dummy/db/schema.rb
@@ -11,12 +11,12 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20150614014411) do
+ActiveRecord::Schema.define(version: 20150722224751) do
 
   create_table "people", force: :cascade do |t|
     t.string   "guid",                  null: false
     t.text     "url",                   null: false
-    t.string   "diaspora_handle",       null: false
+    t.string   "diaspora_id",           null: false
     t.text     "serialized_public_key", null: false
     t.datetime "created_at",            null: false
     t.datetime "updated_at",            null: false