Params validations for Ruby on Rails

ActiveRecord model validation against stopforumspam.com (Rails 3)

Validates wether an association belongs to the same owner

Brazilian zipcode validations for ActiveRecord, integrated with correios-cep gem.

ActiveRecord validations for danish CVR numbers

Some description for validates-gem

Rails 2 and Rails 3 plugin. Validates e-mail address format (RFC2822 and RFC3696) and whitelist/blacklist the domain part.

Use those validators for Australian numbers as ABN, TFN, ...

Validations for making ActiveRecord objects immutable.

Validates uniqueness of has_many children

Validate specific value for Rails

Add to Rails the possibility to validate the quantity of an associate model

SWIFT validator for ActiveRecord attributes.

Validates TeamViewer ID for ActiveRecord attributes.

Library for validating unchangeable attributes.

A notifier for form validation errors.

Find and report ActiveRecord validation errors.

Reuse your Rails model validations on the client-side.

The beginning of a validation library

Ensure that your routes don't conflict. Main use cases are for dynamic routes that could conflict with resourcefully generated routes.