BSV Micropay Middleware

BSV Micropay is a TypeScript toolkit that lets any web service charge sub-cent fees per API call using Bitcoin SV, with zero billing infrastructure and zero human interaction in the payment loop.

It ships as two npm packages:

• @ruthheasman/bsv-micropay-middleware— one line of Express middleware that gates any endpoint behind a 402 Payment Required response. The 402 carries a machine-readable invoice; the server verifies the payment transaction on-chain and lets the request through.

• @ruthheasman/bsv-micropay-client — a fetch wrapper for the caller side. It catches the 402, pays via a pluggable wallet adapter (BRC-100 wallets, HandCash, Yours, Metanet, or a programmatic agent key from @bsv/sdk), and retries automatically.

It supports two modes: a quick address-basedflow for shipping fast, and a fully BRC-121 standards-compliant mode for ecosystem interop. It exposes a .well-known/bsv-micropay-infodiscovery manifest so agents can crawl pricing and capabilities without any prior knowledge of the service.

The whole thing is documented at a live demo site https://bsvmicropay.com (how-it-works, interactive demo, full docs, and a specification section with a comparison table against x402 Agency, Coinbase x402, and Stripe metered billing) and the source is open on GitHub at Ruthheasman/Bsv-Micropay-Middleware.

Use case in one sentence: an AI agent needs data from your API, hits the endpoint, gets quoted a sub-cent price, pays it from its own wallet, and gets the response — all in a single round trip, no sign