# Integration Guides

- [Medusa](/medusa/3.0-beta/integration-guides/medusa.md): Medusa is a REST API that enables you to authenticate your user, apply for a spending limit, create a lease, sign the lease, and perform other operations on behalf of the user.
- [Payment Plugin](/medusa/3.0-beta/integration-guides/payment-plugin.md): The Payment Plugin is an iframe, embeddable in your own site, that enables the user to sign-up or sign-in, apply for a spending limit, enter payment method(s), submit their First Payment, and sign the