GuideRail transforms various data sources into safe, immutable `Data` objects. By leveraging the robust validation capabilities of `dry-schema`, it provides a clear and declarative way to define, validate, and instantiate your data structures.

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

Ruby on Rails plugin for HTML validation and link checking

A library for parameter validation and parsing. A handy way to check GET/POST params in Ruby webframeworks (like Rails or Sinatra).

A DSL for validating request parameters, raises exceptions when validation failed. Currently only supports Rails.

PIS/PASEP validations for pure Ruby and ActiveRecord apps

Thread-safe immutable objects that provide delegation and basic validation to hashes.

Angulate adds AngularJS client-side field and validation helpers to Rails form helpers.

Shorter Active Record validations and associations with RSpec and shoulda support

A lightweight gem that validates required environment variables at application boot time, providing type checking, format validation, and helpful error messages to prevent production disasters caused by missing or invalid configuration.

Rails validations for Belgian Government Registration Numbers (Rijksregisternummer)

Collection of validations for Cod Numeric Personal (CNP), Cod de identificare fiscală (CIF) and IBAN (only Romanian format, as published by Romanian National Bank)

Provides Operation System hashes and validations for rspec-puppet

RStore makes batch processing of csv files a breeze. Automatically fetches data files, directories, URLs :: Customizable using additional options :: Validation of field values :: Descriptive error messages :: Safe and transparent data storage using database transactions

Rubinium is a FIT-style code generator for Selenium. It supports validation and allows the user to include arbitrary ruby in the test.

Includes email and presence validations.

Adds model validations to the host application

This simple_restricted_attributes plugin/gem provides the capabilities to restrict attributes(fields) of db table's while add or update a record. It validate your attributes values before your validation stuff.

Intelligently applies a maxlength attribute for text fields based on column constraints and validations

Validate the phone number and content of an SMS Message. This gem does not send SMS messages. It just makes sure the arguments are valid.