diff --git a/lib/github/representation/base.rb b/lib/github/representation/base.rb
new file mode 100644
index 00000000000..6765bfb803b
--- /dev/null
+++ b/lib/github/representation/base.rb
@@ -0,0 +1,13 @@
+module Github
+  module Representation
+    class Base
+      def initialize(raw)
+        @raw = raw
+      end
+
+      private
+
+      attr_reader :raw
+    end
+  end
+end
diff --git a/lib/github/representation/branch.rb b/lib/github/representation/branch.rb
new file mode 100644
index 00000000000..7c65a948ede
--- /dev/null
+++ b/lib/github/representation/branch.rb
@@ -0,0 +1,52 @@
+module Github
+  module Representation
+    class Branch < Representation::Base
+      attr_reader :repository
+
+      def initialize(repository, raw)
+        @repository = repository
+        @raw = raw
+      end
+
+      def user
+        raw.dig('user', 'login') || 'unknown'
+      end
+
+      def repo
+        return @repo if defined?(@repo)
+
+        @repo = Github::Representation::Repo.new(raw['repo']) if raw['repo'].present?
+      end
+
+      def ref
+        raw['ref']
+      end
+
+      def sha
+        raw['sha']
+      end
+
+      def short_sha
+        Commit.truncate_sha(sha)
+      end
+
+      def exists?
+        branch_exists? && commit_exists?
+      end
+
+      def valid?
+        sha.present? && ref.present?
+      end
+
+      private
+
+      def branch_exists?
+        repository.branch_exists?(ref)
+      end
+
+      def commit_exists?
+        repository.branch_names_contains(sha).include?(ref)
+      end
+    end
+  end
+end
diff --git a/lib/github/representation/label.rb b/lib/github/representation/label.rb
new file mode 100644
index 00000000000..b3140ab76fc
--- /dev/null
+++ b/lib/github/representation/label.rb
@@ -0,0 +1,17 @@
+module Github
+  module Representation
+    class Label < Representation::Base
+      def color
+        "##{raw['color']}"
+      end
+
+      def title
+        raw['name']
+      end
+
+      def url
+        raw['url']
+      end
+    end
+  end
+end
diff --git a/lib/github/representation/milestone.rb b/lib/github/representation/milestone.rb
new file mode 100644
index 00000000000..5ea54eb178f
--- /dev/null
+++ b/lib/github/representation/milestone.rb
@@ -0,0 +1,37 @@
+module Github
+  module Representation
+    class Milestone < Representation::Base
+      def iid
+        raw['number']
+      end
+
+      def title
+        raw['title']
+      end
+
+      def description
+        raw['description']
+      end
+
+      def due_date
+        raw['due_on']
+      end
+
+      def state
+        raw['state'] == 'closed' ? 'closed' : 'active'
+      end
+
+      def url
+        raw['url']
+      end
+
+      def created_at
+        raw['created_at']
+      end
+
+      def updated_at
+        raw['updated_at']
+      end
+    end
+  end
+end
diff --git a/lib/github/representation/pull_request.rb b/lib/github/representation/pull_request.rb
new file mode 100644
index 00000000000..85f4e1bdac3
--- /dev/null
+++ b/lib/github/representation/pull_request.rb
@@ -0,0 +1,123 @@
+module Github
+  module Representation
+    class PullRequest < Representation::Base
+      attr_reader :project
+
+      delegate :user, :repo, :ref, :sha, to: :source_branch, prefix: true
+      delegate :user, :exists?, :repo, :ref, :sha, :short_sha, to: :target_branch, prefix: true
+
+      def initialize(project, raw)
+        @project = project
+        @raw = raw
+      end
+
+      def iid
+        raw['number']
+      end
+
+      def title
+        raw['title']
+      end
+
+      def description
+        raw['body'] || ''
+      end
+
+      def source_project
+        project
+      end
+
+      def source_branch_exists?
+        !cross_project? && source_branch.exists?
+      end
+
+      def source_branch_name
+        @source_branch_name ||=
+          if cross_project? || !source_branch_exists?
+            source_branch_name_prefixed
+          else
+            source_branch_ref
+          end
+      end
+
+      def target_project
+        project
+      end
+
+      def target_branch_name
+        @target_branch_name ||= target_branch_exists? ? target_branch_ref : target_branch_name_prefixed
+      end
+
+      def milestone
+        return unless raw['milestone'].present?
+
+        @milestone ||= Github::Representation::Milestone.new(raw['milestone'])
+      end
+
+      def author
+        @author ||= Github::Representation::User.new(raw['user'])
+      end
+
+      def assignee
+        return unless assigned?
+
+        @assignee ||= Github::Representation::User.new(raw['assignee'])
+      end
+
+      def state
+        return 'merged' if raw['state'] == 'closed' && raw['merged_at'].present?
+        return 'closed' if raw['state'] == 'closed'
+
+        'opened'
+      end
+
+      def url
+        raw['url']
+      end
+
+      def created_at
+        raw['created_at']
+      end
+
+      def updated_at
+        raw['updated_at']
+      end
+
+      def assigned?
+        raw['assignee'].present?
+      end
+
+      def opened?
+        state == 'opened'
+      end
+
+      def valid?
+        source_branch.valid? && target_branch.valid?
+      end
+
+      private
+
+      def source_branch
+        @source_branch ||= Representation::Branch.new(project.repository, raw['head'])
+      end
+
+      def source_branch_name_prefixed
+        "gh-#{target_branch_short_sha}/#{iid}/#{source_branch_user}/#{source_branch_ref}"
+      end
+
+      def target_branch
+        @target_branch ||= Representation::Branch.new(project.repository, raw['base'])
+      end
+
+      def target_branch_name_prefixed
+        "gl-#{target_branch_short_sha}/#{iid}/#{target_branch_user}/#{target_branch_ref}"
+      end
+
+      def cross_project?
+        return true if source_branch_repo.nil?
+
+        source_branch_repo.id != target_branch_repo.id
+      end
+    end
+  end
+end
diff --git a/lib/github/representation/repo.rb b/lib/github/representation/repo.rb
new file mode 100644
index 00000000000..b9cae43450e
--- /dev/null
+++ b/lib/github/representation/repo.rb
@@ -0,0 +1,9 @@
+module Github
+  module Representation
+    class Repo < Representation::Base
+      def id
+        raw['id']
+      end
+    end
+  end
+end
diff --git a/lib/github/representation/user.rb b/lib/github/representation/user.rb
new file mode 100644
index 00000000000..70a0ce000ae
--- /dev/null
+++ b/lib/github/representation/user.rb
@@ -0,0 +1,19 @@
+module Github
+  module Representation
+    class User < Representation::Base
+      def id
+        raw['id']
+      end
+
+      def email
+        return @email if defined?(@email)
+
+        @email = Github::User.new(username).get.fetch('email', nil)
+      end
+
+      def username
+        raw['login']
+      end
+    end
+  end
+end