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