Lightning Labs said Wednesday it has launched a dedicated website for L402, presenting the protocol as a way for AI agents to make payments in bitcoin.
“With L402, agents can pay with bitcoin and natively authenticate. No accounts, no intermediaries, no humans involved,” the company said in its post, calling L402 “the protocol for machine-to-machine commerce on Lightning.”
The launch is for a website, not a new protocol
The new piece here is the site, not the protocol itself. L402, described as the Lightning HTTP 402 protocol, already exists in Lightning Labs’ product stack.
According to the company’s documentation, Aperture, an implementation of the standard, “is used today by Lightning Loop, a non-custodial swap service for Bitcoin and Lightning.”
Lightning Labs frames L402 as infrastructure for AI agents
The documentation describes L402 as “the standard for selling and buying digital resources” and says it “allows services to charge for API endpoints in a way that is easy for AI agents to participate.”
The mechanism reuses HTTP’s 402 status code. When a client requests a gated endpoint, “the server responds with HTTP 402 Payment Required and a WWW-Authenticate header containing a token and a Lightning invoice,” the documentation says. The token includes the invoice’s payment hash.
The client then pays the invoice and presents the token together with the payment preimage to access the endpoint. The server can verify both without querying a payment database, which Lightning Labs describes as stateless verification.
Part of a broader push toward agent-focused payments
The release comes as several firms are building payment tooling aimed at autonomous software agents rather than human users.
Coinbase’s x402 protocol uses the same HTTP status code on Ethereum-based rails and has moved to the Linux Foundation with backing from Google, Stripe, and Visa. Visa has also released a command-line payment tool for AI agents.
L402 takes a different route by sending those payments over Bitcoin’s Lightning Network instead.