Protect the foreign keys in your Rails models by checking the user_id of self against the user_id of all relations.

Add state maps to Rails Enums for validation on transitions.

Ruby Library for the mailboxlayer API, a web service that email validation & verification, https://mailboxlayer.com/

A simple, localizable EachValidator for email address fields in ActiveRecord 3.0.

Mobile MSISDN detection & validation. Only useful whenever your'e a Mobile Operator 3rd Party and receive MSISDN headers.

Small and extensible data validation toolkit

Hashie2 + ActiveModel 3, offering declared properties, validations, JSON serialization/deserialization

Validate presence/absence of resource creation/update and relationship update payloads, as well as types related resources

Having to validate method parameters and/or the result of method is a quite common and repetitive task. Tchae is an attempt to capture this task in a small yet generic reuseable library. Tchae provides validated variants of the standard define_method ruby methods , that will create the same metho...

Validates polish identification numbers NIP, PESEL, REGON. Can be used in any ruby script or integrated with Rails validation

Provides a OneOfManyValidator for Rails validation. This allows you to validate that one of a set of fields should be required, but no particular field itself is required.

Advanced ActiveModel email validation with MX lookups, domain blacklisting and disposable email blocking

Allows Kumi schemas to be written as plain text with syntax validation and editor integration.

This gem is very fast C++ code for calculating AUCs on results of cross-validation. It is specific to the crossval database schema, which has not been released yet. Chances are you will not find this very useful unless you are the author. It is in gem form to ensure that each lab machine can c...

This gem will use ActiveRecord’s existing validates_format#presence#uniqueness_of method to check whether the email parameter has a valid format, is present and is unique

Validation frontend for models. Inspired by the scrivener gem.

Reliable contract definition, data validation, and type checking for Ruby.

A composable application toolkit, providing data entities and collections, transforms, contract-based validations and pre-built operations. Architecture agnostic for easy integration with other toolkits or frameworks.

Dependency-free object validation library for Ruby 1.8.7+

Hat-Trick brings together jQuery, validation_group, and Ajax to make multi-step forms awesome. It tries to insulate you from this complexity by providing a simple yet powerful DSL for defining the steps of your form and their behavior.