Validate email addresses against RFC 2822 and RFC 3696.

Protect attributes from mass assignment

Phone number validation

Cequel is an ActiveRecord-like domain model layer for Cassandra that exposes the robust data modeling capabilities of CQL3, including parent-child relationships via compound primary keys and in-memory atomic manipulation of collection columns.

Dynamoid is an ORM for Amazon's DynamoDB that supports offline development, associations, querying, and everything else you'd expect from an ActiveRecord-style replacement.

Translations for the devise gem

Send e-mail straight from forms in Rails with I18n, validations, attachments and request information.

The only agent-oriented AI framework designed for Rails, where Agents are Controllers. Build AI features with less complexity using the MVC conventions you love.

DynamicForm holds a few helper methods to help you deal with your Rails3 models. It includes the stripped out methods from Rails 2; error_message_on and error_messages_for. It also brings in the functionality of the custom-err-messages plugin, which provides more flexibility over your model error...

Presenting names of people in full, familiar, abbreviated, and initialized forms (but without titulation etc)

ripple is an object-mapper library for Riak, the distributed database by Basho. It uses ActiveModel to provide an experience that integrates well with Rails 3 applications.

Rails performance tests (removed from core in Rails 4.0)

Interact with REST services in an ActiveRecord-like manner

Pure Ruby readonly serializers for the JSON:API spec.

Adds file validators to ActiveModel

ActiveRecord like interface to read only access and query static YAML files

Obscenity is a profanity filter gem for Ruby/Rubinius, Rails (through ActiveModel), and Rack middleware

Rails observer (removed from core in Rails 4.0)

acts_as_api enriches the models and controllers of your app in a rails-like way so you can easily determine how your XML/JSON API responses should look like.

CSV Import for humans