Any company/person can implement. nostr:npub19hg5pj5qmd3teumh6ld7drfz49d65sw3n3d5jud8sgz27avkq5dqm7yv9p is an open standard.
Discussion
Shouldn't the service rely on relays as that how payments work in Nostr? nostr:nprofile1qqszm52qe2qdkc4u7dma0klx3532jka2g8geck6fwxncyp90wktq2xspp4mhxue69uhkummn9ekx7mqprpmhxue69uhhwetvvdhk6efwdehhxarj9emkjmn9qy28wumn8ghj7un9d3shjtnyv9kh2uewd9hsy47788 is just to connect your wallet to the client.