What are the differences to ActiveModel::Serializer?

[ChristianPeters]

Representers seem to fulfill the same purpose as ActiveModel::Serializers do.

Could you point out the differences of these two?

ActiveModel::Serializer is written by two Rails core developers, could have chances to be integrated in Rails, and is the more popular project. Why should I use Representer nevertheless?

[RobWu]

One big difference if that ActiveModel::Serializers does not support xml.
See rails-api/active_model_serializers#39 (comment)