FiletypeValidation is a Ruby gem for validating file content types.

This gem allows model to have state, and based on that create wizard with step by step validations

This is an alpha version. Create a class implements from FluentValidator, then use rule_for method to register validators in its construction method.

Form object helpers built on top of dry-validations

This gem for Ruby on Rails 4.0+ allows to create blocks for each field of the form. This allows to simplify syntax, show errors, add errors classes and validation attributes.

Formtastic's stock BooleanInput doesn't work with client_side_validations. This does.

Rails gem/plugin that implements an ActiveRecord validation helper called validates_as_date_time which validates U.S. dates, times, and date-times

This is a module for the Ruby language that defines a callback GEDCOM parser. It does not do any validation of a GEDCOM file, but, using application-defined callback hooks, can traverse any well-formed GEDCOM.

Clean Language Validation

Providing special validation error building for has_many collection in Rails.

Validations for Non Active Record Models

ActiveModel Validation for CSS

ActiveModel validation against duplicating records.

Lightweight gem that utilizes Rails server-side model validations to display client-side error messages for Ajax form submissions.

Epic validator, wraps validation for HTML, JavaScript and CSS.

Simple way to do validations more clear :)

A runtime validation configuration DSL

Configurator for Ruby Applications with some validation and sugars.

Adds a test that validates all your Rails fixtures.

email validation