Awesome. This is helpful, thanks. You're doing my market research for me!

Seems like most setups only really need 2-3 channels, rather than the ~140 supported by Apprise. Definitely worth me looking into when I start to work towards a v2 release and supporting webhooks in general.

The part I'm not sure about yet is how I'm going to implement it. My current approach is to custom write a transport layer for each provider, so a generic webhook would be the first non-bespoke transport. I don't want to lock myself into the path of writing a bespoke solution for every email provider and every channel (that's basically reimplementing Apprise in Go with better email support). I'm hoping I can get a generic webhook that would be good enough for most use cases.

I'll also need to think about if I want to support an email + webhook use case or pick one per request. If I built that and you deployed it for email + telegram, would that be good enough for your use case? You could also just deploy it alongside Apprise if you have an email need that we handle better (and I think we definitely do, especially once I ship html email in 1.x).

If you do end up using Posthorn, please let me know how it goes and feel free to open up any issues you see on GitHub.