Notify! has no accounts, no SDK, and a published API, so anyone can wire it into their own project without asking permission. These are the ones we know about. If you have built something, tell us and we will list it here.
Built and maintained by their own authors, and Notify! does not control them. The Uptime Kuma provider is the exception: we wrote it and sent it upstream, so Kuma's maintainers own that code now. Every link goes straight to the source.
There is no partner program, no application, and no API key to request. Grab a Device ID and token from the app, and you are already integrated.
Send a link to your repo or plugin listing and a line about what it does. We will take a look and add it to the list above. Your project stays yours.