It's been discussed before, leaving it on GitHub to save it from oblivion.
It would be nice if c-lightning users could use Spark wallet in BTCPay, similar to LND users have with Zap.
I'm not sure what's needed here, but the ability to connect without hassle like with Zap (via QR code or something similar) would be epic.
Pinging @shesek as he might be able to help us with this one.
I have not tested anything yet, but already talked with @shesek about what is needed. He added everything I needed, so it should be good here.
The login file functionality (requested for more convenient integration in BTCPay's docker compose setup) is still an open PR and was not merged to master, but I'll merge as soon as you confirm it works as expected.
Ta-da! Implemented by @NicolasDorier
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I have not tested anything yet, but already talked with @shesek about what is needed. He added everything I needed, so it should be good here.