active_model_changeset

https://github.com/nemuba/active_model_changeset

ActiveModelChangeset provides a lightweight changeset abstraction for Ruby on Rails applications. It combines type casting, attribute normalization, validation and diff calculation into a single object, enabling safe and explicit create/update operations with patch semantics. The gem is designed for service objects and APIs, allowing developers to whitelist attributes, apply transformations, validate input and update models using only changed values, without relying on ActiveRecord callbacks or controllers.