Pay is a Rails-first payments and subscriptions engine that wraps modern providers to give you a clean, idiomatic API for charging customers, managing subscriptions, handling invoices, and processing webhooks.

It is designed to feel like Rails, with generators, models, and background jobs that take care of the heavy lifting so you can ship billing quickly.

Setup typically involves adding the gem, running the installer to create the necessary tables and initializers, configuring your provider keys, and wiring up webhook endpoints.

Pay supports recent Rails versions on Ruby 3+, integrates smoothly with Devise and Active Job, and provides documentation and examples on GitHub as the primary support channel.

Its tight Rails integration, sensible defaults, and production-oriented patterns such as proration and dunning flows set it apart, however, weaknesses include being opinionated around supported providers and conventions, which may feel constraining for highly bespoke billing models.

Actively maintained alternatives include building directly on the Stripe or Braintree SDKs for maximum control or using platform SDKs alongside ActiveMerchant if you need many gateways.