This library helps validate that an attribute is a subset of a specified set

Validates Telephone for Brazil and United States and test it with matchers in a simple way.

Library for validating unchangeable attributes.

Validates if an attribute has a valid xml content or a xsd valid content.

Adds validation methods considering different country zip code formats. Currently, we can validate 130 countries.

Provides an extensible hook for adding custom html attributes to input elements based on validation rules defined in your model.

Delegates validation between objects

Use reflection to spec ActiveModel validations

Scope ActiveModel validations

A extension activemodel's validations to validation step by step.

A collection of delicious Rails validators

contextual validations for controllers and wanna learn to do other stuff good too

ActiveModel validation for credit card number.

Your favourite validations with Ruby

Valid-env allows you to specify the environment variables that are required, those that are optional, and those that depend on one another, and will throw a useful error message immediately if something is missing.

Extension to ActiveModel for validating hostnames

VAT Identification Number validation

VAT-ID validator based on ActiveModel::EachValidator

Vat number validator for Rails 3+ using vatlayer.com API

A Ruby wrapper library for veritrans Air Direct API