Databases on Rails. Build a persistent domain model by mapping database tables to Ruby classes. Strong conventions for associations, validations, aggregations, migrations, and testing come baked-in.

A toolkit for building modeling frameworks like Active Record. Rich support for attributes, callbacks, validations, serialization, internationalization, and testing.

A high-level IO library that provides validation, type conversion, and more for command-line interfaces. HighLine also includes a complete menu system that can crank out anything from simple list selection to complete shells with just minutes of work.

Validation library

Library for performing validations on DM models and pure Ruby object

Rack::Cache is suitable as a quick drop-in component to enable HTTP caching for Rack-based applications that produce freshness (expires, cache-control) and/or validation (last-modified, etag) information.

RSpec matches for Mongoid models, including association and validation matchers.

A Ruby wrapper for the World Wide Web Consortium’s online validation services.

dry-schema provides a DSL for defining schemas with keys and rules that should be applied to values. It supports coercion, input sanitization, custom types and localized error messages (with or without I18n gem). It's also used as the schema engine in dry-validation.

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 specification. Check out the README for some examples of how easy it is. Best of all, you can validate your xlsx file before serialization so you know for sure that anything generated is going to load on your client's machine.

CouchRest Model provides aditional features to the standard CouchRest Document class such as properties, view designs, associations, callbacks, typecasting and validations.

Validatable is a library for adding validations.

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 specification. Check out the README for some examples of how easy it is. Best of all, you can validate your xlsx file before serialization so you know for sure that anything generated is going to load on your client's machine.

Send e-mail straight from forms in Rails with I18n, validations, attachments and request information.

Validatable is a library for adding validations.

Adds validation methods to ActiveModel for validating dates and times. Works with multiple ORMS.

Google libphonenumber library was taken as a basis for this gem. Gem uses its data file for validations and number formatting.

Say goodbye to clunky, confusing alerts and form validation notifications on your website! PHCDevworks offers easy-to-use Rails 7 helper engine and partial views that can help you implement clear, concise, and user-friendly alerts.

Membrane provides an easy to use DSL for specifying validation logic declaratively.

Client Side Validations made easy for your Rails 5 applications