A State Machine implementation of a UTF-8 Encoding Validation algorithm.

extend ActiveRecord validations by checking if a string is a valid email address

Rails gem/plugin that implements an ActiveRecord validation helper called validates_as_email which validates email address (RFC822)

Rails gem that implements an ActiveRecord validation helper called validates_as_postal_code which validates U.S. postal codes

API for the metadata validation service.

Makes boolean validations a little cleaner.

Automatic field validation for forms backed by DataMapper models through Sinatra.

Validations for Ruby objects

Valentine is a simple validation library for JSON and ordinary Hash based on an easy Hash based syntax.

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

Rails plugin that provides a validates_ip_format_of method to ActiveRecord models. IPs are validated by regexp. IP validation. Validate IP.

A simple gem for email validation.

EachValidator that adds a parent model's association's validation errors to the parent model

An ActiveModel validator utilizing the built in URI parse methods to provide a rich semantic API for URI validation

Allows one to implement object validations without writing too much code

Rails gem that implements an ActiveRecord validation helper called validates_as_phone_number which validates U.S. phone numbers

Validations for making ActiveRecord objects immutable.

The beginning of a validation library

Valvat_cache caches in a json file results of the VIES validation keeping it a couple of weeks

This gem unions a server-side ActiveModel password strength validation plugin with a client-side password strength estimation