Creating a registrar integration
This guide is incomplete. Please help us complete it using the "Edit this page" button in the sidebar. Thanks! If you're looking to create your own extension, this documentation will tell you the bare minimum required, but looking at existing extensions will probably be necessary to get a complete idea on how to write one.
All domain registrars should reside under the /library/Registrar/Adapter folder. They should all extend the Registrar_AdapterAbstract class and implement it's functions.
The Registrar_AdapterAbstract class has inline documentation of each function to aid in the development of domain registrars. You can find the most up-to-date version of this here (opens in a new tab)