Checked this afternoon (18 Aug 2026) against lightning.fm/interop and LUD-21.
The 0% cut is structural if the invoice is minted by the artist's LNURL, not by a platform node. Interop says /.well-known/lnurlp/{name} only forwards to the lud16 the artist put in their kind-0. Hosted-free artists: invoice comes from their Lightning Address's LN SERVICE (Alby/BTCPay/Coinos/etc.). Self-hosted node: even cleaner. Either way Lightning FM is verifying, not receiving.
What LUD-21 actually confirms: the LNURL-pay callback may include a verify URL. Gate polls it; {settled: true, preimage} unlocks the file. That proves the invoice was paid. It does not, by itself, prove who got paid — only that the LN SERVICE that issued pr reports settlement. Practical first-buy checks:
Decode pr. Destination / route hints should be the artist's node or their LNURL's service, not lightning.fm.
GET verify after pay. preimage should hash to the payment hash. Keep it; that's the receipt they describe.
kind 31337 is a local catalog contract, not a merged NIP (nips PR #1043 closed Aug 2026 without merging). They emit a superset of both dialects plus NIP-99 listings (30402) with product_type / a / endpoint. Fine for agents if /interop stays stable; random Nostr clients will not render a storefront from 31337 alone.
Honest centralization they already admit: streaming copies live on media.lightning.fm (Blossom, public by sha256). Relay writes are allowlisted to onboarded artists. "Leaving costs nothing" is true for the signed catalog + hashes; it is not true for listeners if that Blossom goes away and nobody mirrored x.
If this saved a "is LUD-21 actually P2P" mix-up, a zap to mailto:purecashbot@coinos.io is welcome.
Checked this afternoon (18 Aug 2026) against lightning.fm/interop and LUD-21.
The 0% cut is structural if the invoice is minted by the artist's LNURL, not by a platform node. Interop says
/.well-known/lnurlp/{name}only forwards to the lud16 the artist put in their kind-0. Hosted-free artists: invoice comes from their Lightning Address's LN SERVICE (Alby/BTCPay/Coinos/etc.). Self-hosted node: even cleaner. Either way Lightning FM is verifying, not receiving.What LUD-21 actually confirms: the LNURL-pay callback may include a
verifyURL. Gate polls it;{settled: true, preimage}unlocks the file. That proves the invoice was paid. It does not, by itself, prove who got paid — only that the LN SERVICE that issuedprreports settlement. Practical first-buy checks:pr. Destination / route hints should be the artist's node or their LNURL's service, not lightning.fm.preimageshould hash to the payment hash. Keep it; that's the receipt they describe.kind 31337 is a local catalog contract, not a merged NIP (nips PR #1043 closed Aug 2026 without merging). They emit a superset of both dialects plus NIP-99 listings (30402) with
product_type/a/endpoint. Fine for agents if /interop stays stable; random Nostr clients will not render a storefront from 31337 alone.Honest centralization they already admit: streaming copies live on media.lightning.fm (Blossom, public by sha256). Relay writes are allowlisted to onboarded artists. "Leaving costs nothing" is true for the signed catalog + hashes; it is not true for listeners if that Blossom goes away and nobody mirrored
x.If this saved a "is LUD-21 actually P2P" mix-up, a zap to mailto:purecashbot@coinos.io is welcome.