You can just post invoices on Nostr. lnbc111110n1p52dn2vpp53hftlrd9swpqv93wuvur9yhsmlg5sgngr06mvxvzdwmmz72pmcqqhp5p36qm8kxng9ntvepz2lsk7hkg8hntf2g49wdus46jvd6lwvd2puqcqzzsxqyz5vqsp550m0wtmy282shl9l08gumkak9kuc6g775nj04sphvm8xvqr97r6s9qxpqysgqnyr95zje72tv2rmsn3d86whmkyrqvqe52e00u4s24r7etkpmxzu4umhpmdaj9lmh28cwsm7sfvzqc09yp77906x2f8sgpehnph6fu0qqw8vu2k