A Rails plugin that adds an ActiveRecord validation helper to do range and start/end date checking in.

A custom validation for your Active Model that check if an array is included in another one

Swift code validation and lookup Ruby gem

Schema-based validation and coercion for Ruby data structures, inspired by Prismatic/schema for Clojure.

CPF and CNPJ validations for ActiveModel and Rails

Keep your code DRY by inferring column validations from table properties! Automagically validate presence, length, numericality, inclusion and uniqueness of ActiveRecord backed columns.

A development toolkit for Ruby with several small/cohesive abstractions (monads, enums, business logic, data validation...) to empower your development workflow - It's totally free of dependencies.

This gem preps a new Rails app with some of the best Rails gems and Jquery sweetness available( Twitter-Bootstrap, Devise, CanCan, Rails Admin, Spreadsheet, ) Not only does it takes care of the installation of these gems, it also extends your scaffolds to give aesthetically improved views. Furthe...

Headhunter is an HTML and CSS validation tool that injects itself into your Rails feature tests and automagically checks all your generated HTML and CSS for validity. In addition, it also looks out for unused (and therefore superfluous) CSS selectors.

IBAN + SWIFT/BIC: Information, Validation and Formatting.

Personnummer handles validation of Swedish personal identity numbers.

RFC822 compatible email validation and MX record check

Decode iTunes OS X and iOS receipts without remote server-side validation by using the Apple Inc Root Certificate.

A Ruby Library for dealing with validation cryptocurrency adresses.

Provides a form field validation JavaScript library for your Rails application. Built for use with jQuery and Twitter Bootstrap 3. Source code: https://github.com/nghuuphuoc/bootstrapvalidator

Validate iTunes Transaction and Unified style receipts with local decoding and remote validation.

ActiveModel validation that checks email addresses against a blacklist of trash-mail providers

A small wrapper around ActiveModel Validations.

Ruby gem for runtime data validation and monitoring using the contracts approach.

LHS ia a Rails-Gem, providing an ActiveRecord like interface to access HTTP-JSON-Services from Rails Applications. Special features provided by this gem are: Multiple endpoint configuration per resource, active-record-like query-chains, scopes, error handling, relations, request cycle cache, batc...