Lightning Labs Adds Bitcoin Payments for AI Inference to Pi Coding Agent

Lightning Labs launched pi402, an open-source extension that lets the Pi coding agent pay for AI inference with Bitcoin (BTC) over the Lightning Network, giving developers a way to charge agents for the tokens they use.

When an agent requests a paid service, the server responds with an HTTP 402 payment request and a Lightning invoice. The agent pays the invoice to access the service. The pi402 flow uses the L402 protocol and macaroons, a type of credential token, for authentication, while billing is based on tokens consumed rather than a monthly plan or prepaid balance.

Inference providers can pair Aperture, an L402 reverse proxy, with Lightmeter to meter usage and accept payments for OpenAI-compatible endpoints. The Wavelength wallet processes payments and moves funds between Ark and Lightning. Buyers and sellers do not need to run Lightning nodes or manage payment channels.

Demo pricing is about $0.375 per million input tokens and $1.50 per million output tokens. The launch follows Lightning Labs’ October mainnet launch of Wavelength for AI agent payments, which enables agents to send and receive BTC over Lightning without requiring a person to approve each transaction.