Rails 3 awesome custom validators

Validacity adds an extra layer of validation objects where all your validation logic can be moved to.

Validates Cnpj

Validates CPF

Simple gem helpful in validating standard credit card forms

Use ActiveModel to validate arguments for any Ruby method

Adds validates_associated_with_context to models to validate associated models with validation context

ActiveModel validation that two associated models are related to each other.

Validates CNPJ and test it with matchers in a simple way.

Brazilian zipcode validations for ActiveRecord, integrated with correios-cep gem.

Validates CPF and test it with matchers in a simple way.

Validates CURP and test it with matchers in a simple way.

An advance email validator. Checks format, MX record existence for email domain, and SMTP address validation.

An ActiveModel validator utilizing the built in URI parse methods to provide a rich semantic API for URI validation

Validates Guatemala Identity Document and test it with matchers in a simple way.

Validates Host, Domain and IP and test it with matchers in a simple way.

Validates Several Identity Documents and test it with matchers in a simple way.

Validates Argentina DNI Document and test it with matchers in a simple way.

Validates Brazilian CNPJ Document and test it with matchers in a simple way.

Validates Brazilian CPF Document and test it with matchers in a simple way.