100% exclusive message for any ActiveModel validation error.

It provides basic command line tools for simply defining things like cross validations, factorial experimental design and basic statistics. All of this can be run in a distributed manner.

Interdependent model validations

Simple recaptcha plugin which allows to add reCAPTCHA validations to your forms

Provides subset validation for serialized arrays or sets in Active Record

A gem that handles your form and query validation in an elegant way.

Bailitheoir is a JavaScript that you can insert into your pages to ensure that the browser will implement form input validation.

Versions validations and comparisons!!!

Get validation error from database constraint.

Cave Forms encapsulate validation logic into an object with that single responsibility

Imports delimited text files to Active Record or Datamapper, with validations.

Use the familiar ActiveModel::Errors pattern for controller validations

Detects issuer from a number, has ActiveModel validations and translations support.

A simple library for external validations of POROs

Uses dry-validation

A simple plugin to assist ELS token validation

html_pretty is yet another HTML prettifier. It purposefully does not do parsing or validation.

Hval 🐳 is hash validation gem

Custom ActiveModel::Validations to Make Your Life Easier

Provides validation and proper formatting for ISBN13 numbers.