# Developers

- [Getting started](/developers/getting-started.md): Integrate your apps, plugins and extensions with Retainful using our simple, developer-friendly RESTful API
- [Authentication](/developers/authentication.md): Learn how to authenticate your app or integration with Retainful in order to use the API
- [Contacts](/developers/contacts.md): Learn how to send contacts to Retainful API
- [Lists](/developers/lists.md): Learn how to retrieve the lists from Retainful API