Lightning Labs ships pi402 so AI agents can pay for inference in Bitcoin

Lightning Labs unveiled pi402 on November 12, 2026. The open-source extension plugs into the Pi coding agent and lets it settle its own inference bills in Bitcoin over the Lightning Network, according to Crypto Briefing. There is no account to create, no API key to paste and no credit card on file. The agent reads a price, pays the invoice and goes back to work.

The machinery is L402, a protocol Lightning Labs has been building for a while. It welds together two things that were never meant to meet: the HTTP 402 'Payment Required' response and a Lightning invoice requesting a set amount of Bitcoin. When an agent hits a paid endpoint, the server fires back a 402 with an invoice attached. The agent pays, the payment clears instantly, and macaroons handle authentication.

The payoff is pay-per-token billing. No monthly plans, no prepaid balances — the agent pays for exactly the tokens it burns, request by request. Once it's configured, the loop runs itself. Demo pricing sits at roughly $0.375 per million input tokens and $1.50 per million output tokens.

Sellers need a way to collect, so Lightning Labs points them to two of its own tools. Aperture is an L402 reverse proxy that enforces pay-first, access-later logic before requests reach the backend. Lightmeter sits alongside it to meter usage and accept payments, letting a provider charge for an OpenAI-compatible inference endpoint. Neither side has to run a Lightning node or babysit payment channels — the Wavelength wallet handles that, built on Ark and shifting funds automatically between Ark and Lightning.

pi402 caps a 2026 run that all pointed the same way. In February, Lightning Labs launched agent tooling for software interacting with Lightning payments. In October, Wavelength went live on mainnet. Agent tools gave machines a way to transact, Wavelength killed the node-management headache, and pi402 now packages both into something a coding agent can use to buy the thing it actually needs: inference.