Rail402

x402 payments infrastructure for Stellar: a facilitator, a discovery layer (Bazaar), an MCP server for agents, a payments explorer, and the SDKs to build on all of it.

Live facilitator (testnet): https://facilitator.rail402.dev

What's here

Directory	What it is
apps/facilitator	x402 verify / settle / supported service for stellar:testnet, with sponsored fees and the Bazaar co-deployed
apps/bazaar	catalog, automatic cataloging at verify/settle, /discovery/resources and /discovery/search (hybrid BM25 + embedding ranking)
apps/mcp-discovery	MCP server exposing search and a spend-capped paid-call tool
apps/explorer	indexes and classifies x402 settlements from the Stellar ledger, serves a public read API
apps/cli	command-line wallet and agent tool (rail402)
apps/playground	interactive demo of the discover → pay loop
apps/docs	documentation site
packages/*	error registry, seller/agent helpers, the upto scheme, conformance harness, canaries, umbrella SDK
contracts/	Soroban contracts: upto settlement and an agent spending policy
examples/	end-to-end integrations: paid API + agent, MCP tool seller, smart-account buyer

Payment schemes: exact and upto (authorize a ceiling, settle actual usage — backed by a small Soroban contract). Buyers can be classic keypairs or smart accounts; network fees are sponsored so buyers need no XLM.

Run it

pnpm install
pnpm --filter @rail402.dev/facilitator dev   # needs a funded testnet secret, see apps/facilitator/.env.example

Or with Docker (facilitator + Bazaar in one image):

docker build -t rail402 . && docker run -p 8080:8080 --env-file .env rail402

Checks

pnpm verify   # lint + typecheck + tests + dependency license gate
pnpm test

Settlement evidence (transaction hashes, conformance runs, rejection audits) is generated into docs/status/.

Packages

Published under the @rail402.dev scope on npm.

License

Apache-2.0. See LICENSE and NOTICE.