diff --git a/lib/diaspora_federation/validators.rb b/lib/diaspora_federation/validators.rb
index 416e992..8fea8c3 100644
--- a/lib/diaspora_federation/validators.rb
+++ b/lib/diaspora_federation/validators.rb
@@ -1,6 +1,5 @@
 require "validation"
 require "validation/rule/regular_expression"
-require "validation/rule/uri"
 
 # +valid+ gem namespace
 module Validation
@@ -20,6 +19,7 @@ require "diaspora_federation/validators/rules/guid"
 require "diaspora_federation/validators/rules/not_nil"
 require "diaspora_federation/validators/rules/public_key"
 require "diaspora_federation/validators/rules/tag_count"
+require "diaspora_federation/validators/rules/uri"
 
 module DiasporaFederation
   # Validators to perform basic sanity-checks on {DiasporaFederation::Entities federation entities}.
diff --git a/lib/diaspora_federation/validators/person_validator.rb b/lib/diaspora_federation/validators/person_validator.rb
index 1995b21..4ccd12a 100644
--- a/lib/diaspora_federation/validators/person_validator.rb
+++ b/lib/diaspora_federation/validators/person_validator.rb
@@ -8,7 +8,7 @@ module DiasporaFederation
 
       rule :diaspora_id, :diaspora_id
 
-      rule :url, :URI
+      rule :url, %i(not_nil URI)
 
       rule :profile, :not_nil
 
diff --git a/lib/diaspora_federation/validators/rules/uri.rb b/lib/diaspora_federation/validators/rules/uri.rb
new file mode 100644
index 0000000..97d9a06
--- /dev/null
+++ b/lib/diaspora_federation/validators/rules/uri.rb
@@ -0,0 +1,41 @@
+module Validation
+  module Rule
+    # URI validation rule
+    #
+    # This rule is based on https://github.com/zombor/Validator/blob/master/lib/validation/rule/uri.rb
+    #
+    # It allows +nil+, so maybe add an additional {Rule::NotNil} rule.
+    class URI
+      # @param [Array<Symbol>] parts the parts that are required
+      def initialize(parts=%i(scheme host))
+        @required_parts = parts
+      end
+
+      # The error key for this rule
+      # @return [Symbol] error key
+      def error_key
+        :URI
+      end
+
+      # This rule has a +required_elements+ param
+      # @return [Hash] params
+      def params
+        {required_elements: @required_parts}
+      end
+
+      # Determines if value is a valid URI
+      def valid_value?(uri_string)
+        return true if uri_string.nil?
+
+        uri = URI(uri_string)
+        @required_parts.each do |part|
+          return false if uri.public_send(part).nil? || uri.public_send(part).empty?
+        end
+
+        true
+      rescue ::URI::InvalidURIError
+        false
+      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
index e4811cc..6a65a6b 100644
--- a/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/birthday_spec.rb
@@ -6,6 +6,10 @@ describe Validation::Rule::Birthday do
     }.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))
diff --git a/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
index dc32f9a..74dc2e5 100644
--- a/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/boolean_spec.rb
@@ -6,6 +6,10 @@ describe Validation::Rule::Boolean do
     }.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
diff --git a/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
index f1f7a0e..072004e 100644
--- a/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/diaspora_id_spec.rb
@@ -6,6 +6,10 @@ describe Validation::Rule::DiasporaId do
     }.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"))
diff --git a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
index 5cd0b82..272adfb 100644
--- a/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/guid_spec.rb
@@ -6,6 +6,10 @@ describe Validation::Rule::Guid do
     }.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"))
diff --git a/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
index 67d5646..ae5d1e6 100644
--- a/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/not_nil_spec.rb
@@ -6,6 +6,10 @@ describe Validation::Rule::NotNil do
     }.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"))
diff --git a/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
index efe461c..f4eb9ca 100644
--- a/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/public_key_spec.rb
@@ -1,4 +1,4 @@
-describe Validation::Rule::Guid do
+describe Validation::Rule::PublicKey do
   it "will not accept parameters" do
     validator = Validation::Validator.new({})
     expect {
@@ -6,6 +6,10 @@ describe Validation::Rule::Guid do
     }.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
diff --git a/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
index e7a1ae7..a54e846 100644
--- a/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
+++ b/spec/lib/diaspora_federation/validators/rules/tag_count_spec.rb
@@ -15,6 +15,10 @@ describe Validation::Rule::TagCount do
     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" }
 
diff --git a/spec/lib/diaspora_federation/validators/rules/uri_spec.rb b/spec/lib/diaspora_federation/validators/rules/uri_spec.rb
new file mode 100644
index 0000000..47cdd03
--- /dev/null
+++ b/spec/lib/diaspora_federation/validators/rules/uri_spec.rb
@@ -0,0 +1,61 @@
+describe Validation::Rule::URI do
+  it "has default params" do
+    expect(described_class.new.params).to eq(required_elements: %i(scheme host))
+  end
+
+  it "has an error key" do
+    expect(described_class.new.error_key).to eq(:URI)
+  end
+
+  context "validation" do
+    it "validates a valid uri" do
+      validator = Validation::Validator.new(OpenStruct.new(uri: "http://example.com"))
+      validator.rule(:uri, :URI)
+
+      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, :URI)
+
+      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, :URI)
+
+      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, :URI)
+
+        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, :URI)
+
+        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, URI: %i(host path))
+
+        expect(validator).not_to be_valid
+        expect(validator.errors).to include(:uri)
+      end
+    end
+  end
+end
diff --git a/spec/support/shared_validator_specs.rb b/spec/support/shared_validator_specs.rb
index 9675b84..e2ce8fc 100644
--- a/spec/support/shared_validator_specs.rb
+++ b/spec/support/shared_validator_specs.rb
@@ -125,6 +125,15 @@ shared_examples "a name validator" do
 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"))