ActiveModel validation for email. Including MX lookup and disposable email blacklist

SimpleForm Plugin for ClientSideValidations

Phone number parsing, validation and formatting.

Parameter Validation and Type Coercion for Rails

ActiveModel Validation for email

Simple model and validation mixins for RubyMotion

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

A ruby gem for validating credit card numbers

cucumber-api allows API JSON response validation and verification in BDD style.

StripAttributes automatically strips all ActiveRecord model attributes of leading and trailing whitespace before validation. If the attribute is blank, it strips the value to nil.

Phone number parsing, validation and formatting

Adds zipcode validation methods to ActiveModel considering different country zipcode formats.

Validations mixin for Ruby objects and support for Lotus

ActiveValidators is a collection of ActiveModel/ActiveRecord validations

Provide an easy way to check the consistency of the database constraints with the application validations.

ActiveRecord Tableless Models provides a simple mixin for creating models that are not bound to the database. This approach is useful for taking advantage of the features of ActiveRecord such as validation, relationships, etc.

Library for performing validations on DM models and pure Ruby object

Realtime remote form input validations delivered via websockets

A gem/plugin for Rails 3+ that enables client-side validation using ActiveModel + HTML5

SchemaValidations extends ActiveRecord to automatically create validations by inspecting the database schema. This makes your models more DRY as you no longer need to duplicate NOT NULL, unique, numeric and varchar constraints on the model level.