A Ruby wrapper for the World Wide Web Consortium’s online validation services.

Robust options validation for methods.

Regressor generates regression specs based on ActiveRecord models. Currently relations, validations, attributes, and database indexes are supported.

Rails plugin that maps model validations to class names on form elements to integrate with Validatious.

Phone number parsing, validation and formatting

Includes a couple of core functions such as callbacks, timestamping, typecasting and lots of generic validation routines.

Introspects your database string field maximum lengths and automatically defines length validations.

ActiveRecord Tableless Models provides a simple mixin for creating models that are not bound to the database. This approach is useful for taking advantage of the features of ActiveRecord such as validation, relationships, etc.

Minimalist validation matcher

Add a validation filter to your controller.

ActiveRecord extension. Allows to save record without calling callbacks and validations.

cucumber-api allows API JSON response validation and verification in BDD style.

Machinery is a systems management toolkit for Linux. It supports configuration discovery, system validation, and service migration. It's based on the idea of a universal system description.

Automatically includes Modules from app/concerns/<module_with_concerns>/<concern>.rb into <module_with_concerns> to ease monkey-patching associations and validations on ActiveRecord::Base descendents from other gems when layering schemas.

A gem that provides credit card validation. It is basically a ruby port of the javascript credit card validator by Thomas Fuchs (madrobby) (http://github.com/madrobby/creditcard_js).

Config. Defined as a class. Used as an instance. Support for inheritance and composition. Lazy instantiation. Thread-safe. Command-style DSL. Validation layer. Support for YAML, TOML, JSON, __END__, ENV. Extremely simple to define. Extremely simple to use.

Adds validation methods to ActiveModel for validating dates and times. Works with multiple ORMS.

Validatable is a library for adding validations.

CPF validation for ActiveModel

Scrivener removes the validation responsibility from models and acts as a filter for whitelisted attributes.