Easily add Judge client side validation to your Formtastic forms.

ActiveRecord: Simple filtering for html as validation.

This gem helps you to create real validation for email, not just a simple regex

This RubyGem allows you to prevent particular database fields from being changed after an Active Record object is created. A validation error occurs on updates if an attribute of a model object is different from its value in the database.

Rack middleware for Discord Interaction validation.

Merb plugin that provides a Form Builder that will wrap your bound fields with a field div, integrated with the model validation

A rails plugin to set the digested value before validation and validate uniqueness.

YAML files loader with validation

Library to parse X12 messages and manipulate their loops, segments, fields, composites, and validation tables.

A Guilded (http://github.com/midas/guilded/tree/master) component that highlights form fields when they are selected or when they have a validation error.

Store mixed numbers in an ActiveRecord model seamlessly with built-in validation.

Modify model fields before validation