xlsx spreadsheet generation with charts, images, automated column width, customizable styles and full schema validation. Axlsx helps you create beautiful Office Open XML Spreadsheet documents ( Excel, Google Spreadsheets, Numbers, LibreOffice) without having to understand the entire ECMA spec...

A validation library for ActiveRecord models that allows introspection (User.name_is_required?) and supports database normalization (aka "form input cleaning").

Validation for Dutch bank account numbers, Citizen Service Numbers (BSN) and Payment reference

Explicit parameters validation and casting for Rails APIs

Parameter whitelisting for Sinatra. Provides validation, defaults, and post-processing.

Easy client side validation for your ActiveRecord models

Provides more advanced and flexible 'if then then that' style conditional validation. Validate fields based on the values of other fields in your model.

Use Turnstile by Cloudflare to perform captcha validation in your Rails app

Interface to the W3C Feed Validation online service http://validator.w3.org/feed/

ISO Schematron Validation

ActiveModel email validation. Checks MX records, sub address, regex, whitelisted and blacklisted check

Simple and composable validation and coercion of data structures inspired by clojure specs

This ruby gem converts time of day to seconds (since midnight) and back. The value in seconds can be used for calculations and validations.

Gem includes validations, card brand detection method, etc.

Optout helps you write code that will call exec() and system() like functions. It allows you to map hash keys to command line arguments and define validation rules that must be met before the command line options are created.

Adds validation methods to ActiveModel for validating phone numbers.

Provides a form field validation JavaScript library for your Rails application. Built for use with jQuery and Twitter Bootstrap 3. Source code: https://github.com/nghuuphuoc/bootstrapvalidator

Validate your ActiveRecord models on the client, showing their error and success messages by providing a validation controller.

Allows defining structure of data and perform validation against it using json-schema

It validates request params outside your controller logic in order to get a clean and nice code, and also helping with the documentation of the operations.