I wonder too. Maybe the 5 pillars of LN backends:
createinvoice, payinvoice, checkinvoice, checkpayment, balance
Discussion
I wish there was a standard api. I suggested something a long time on the lightning-dev/cln mailing list but noone seemed interested.
https://lists.ozlabs.org/pipermail/c-lightning/2022-January/000214.html