RSpec matches for Mongoid models, including association and validation matchers.

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

Client Side Validations made easy for your Rails 5 applications

Robust options validation for methods.

Automatically includes Modules from app/concerns/<module_with_concerns>/<concern>.rb into <module_with_concerns> to ease monkey-patching associations and validations on ActiveRecord::Base descendents from other gems when layering schemas.

Library for performing validations on DM models and pure Ruby object

A ruby gem for validating credit card numbers

Parameter Validation and Type Coercion for Rails

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

A Ruby wrapper for the World Wide Web Consortium’s online validation services.

Useful to make forms and validations. It uses MaxMind database.

A gem that provides credit card validation. It is basically a ruby port of the javascript credit card validator by Thomas Fuchs (madrobby) (http://github.com/madrobby/creditcard_js).

SimpleForm Plugin for ClientSideValidations

Introspects your database string field maximum lengths and automatically defines length validations.

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

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

Adds validation methods to ActiveModel for validating dates and times. Works with multiple ORMS.

A CocoaPods plugin that allows disabling Podfile validations.

CPF validation for ActiveModel

Phone number parsing, validation and formatting