diff --git a/app/serializers/asciicast_serializer.rb b/app/serializers/asciicast_serializer.rb
index e52b926..621e6ee 100644
--- a/app/serializers/asciicast_serializer.rb
+++ b/app/serializers/asciicast_serializer.rb
@@ -5,6 +5,10 @@ class AsciicastSerializer < ActiveModel::Serializer
   attribute :terminal_columns, key: :width
   attribute :terminal_lines, key: :height
 
+  def id
+    object.to_param
+  end
+
   def private?
     object.private?
   end
diff --git a/spec/serializers/asciicast_serializer_spec.rb b/spec/serializers/asciicast_serializer_spec.rb
index 9ef818c..11d37c4 100644
--- a/spec/serializers/asciicast_serializer_spec.rb
+++ b/spec/serializers/asciicast_serializer_spec.rb
@@ -9,7 +9,7 @@ describe AsciicastSerializer do
     subject { JSON.parse(serializer.to_json) }
 
     it 'includes id' do
-      expect(subject['id']).to eq(asciicast.id)
+      expect(subject['id']).to eq(asciicast.to_param)
     end
 
     it 'includes duration' do