Definition
LNURL is a family of open standards (the LUD series) that wrap interactions with a Lightning service inside a bech32-encoded HTTPS URL, typically prefixed lnurl1 and presented as a QR code or an lightning: link. Instead of a one-shot BOLT11 invoice, an LNURL points a wallet at a server endpoint it can query, so a single static code can drive a whole multi-step flow.
The subprotocols
LNURL is split into tag-identified subprotocols. LNURL-pay (LUD-06) returns a callback plus min/max sendable amounts and lets a static code accept arbitrary payments. LNURL-withdraw lets a service authorise a wallet to pull funds, useful for faucets and ATMs. LNURL-auth (LUD-04) provides password-free login by signing a challenge. LNURL-channel requests an inbound channel from a peer. Because the wallet decodes the URL and follows the tag, the same scanning UX covers every case.
Why it underpins so much
LNURL is the connective tissue beneath several higher-level conveniences. Lightning Address is essentially LNURL-pay behind a human-readable identifier, and Nostr Zaps extend the LNURL-pay request with a Nostr event. Servers must return JSON payloads over HTTPS (or HTTP for onion services) and avoid redirects, keeping the trust boundary explicit.
For the convenience layers built on top, compare with Lightning Address. D-Central tracks these standards so sovereign Bitcoiners can self-host receiving infrastructure rather than lean on a custodian.
In Simple Terms
LNURL is a family of open standards (the LUD series) that wrap interactions with a Lightning service inside a bech32-encoded HTTPS URL, typically prefixed lnurl1…