Shows what a field expects before validation fails — complementary to ActiveModel errors.

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

Validaty has basic validations for Rails application

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.

VAT Identification Number data object and validator

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

This Gem acts as an API Client for the VersaCommerce Theme API.

Auto generating ActiveModel validations for hashes

Interface for Pure-FTPd

It provides validation of URIs (URLs) to ActiveModel records and ActionControllers in Rails 3.

Concerns to help manage attributes in View Components

A ViewComponent extension that adds a `prop` DSL with defaults, fallbacks, required props, casting, enum validation, custom validators, and a pluggable caster registry. Patches ViewComponent::Base via a Rails Railtie (or on require outside Rails) so components accept a props hash out of the box.