Two sides, four steps
AgentSmith sits between an agent that has a task and a service that charges for it. Neither side needs an account with the other, an API key, or a prior integration — the four steps below are the whole relationship.
Steps 2 and 3 are a single call from the agent's side — the diagram separates them because each is a point where a payment can be refused, and every refusal comes back with a machine-readable reason.
Three things we do better
Settlement on Stellar is largely solved — we compose the Apache-2.0
@x402/stellar package rather than reimplement it. What decides whether any of this
is usable sits in three places.
Higher natural-language accuracy
We parse an agent's request into the capability it wants and the constraints it must respect before we retrieve anything, so intent and budget are matched separately instead of competing. Accuracy is scored on a golden set of agent-phrased queries in CI.
Ranking backed by a confidence score
Every result carries a calibrated confidence, not just a position, so an agent can tell a strong match from the best of a weak field — and decline to spend below its threshold.
A payment flow built for Stellar
The buyer signs a Soroban auth entry scoped to one exact call rather than handing over a pre-signed transaction, and we sponsor the network fee. We are never the source of funds and never take custody.
Integrate payments with the AgentSmith SDK
One package for Seller payment middleware and Node Buyer paid fetch. Use exact pricing or experimental upto metering with official x402 components. Requires Node.js 24+; discovery helpers are a future delivery.
It points at the AgentSmith Facilitator, which runs on both Stellar testnet and mainnet:
| Environment | Facilitator | Authentication |
|---|---|---|
| Testnet | https://testnet.agentsmith.xyz/facilitator | No API key required |
| Mainnet | https://mainnet.agentsmith.xyz/facilitator | Seller API key required |
SDK quick start → Seller integration → Buyer integration → View on npm →
Pick the side you are on
Find and pay for services →
Use the payment SDK to call paid services. Discovery over HTTP and MCP is a separate workflow. Pay per call with exact, or
authorize a cap and settle actual usage with upto.
Charge per request →
Protect an Express API route with the SDK, set a token price, and let the Facilitator verify and settle payments. Bazaar discovery is a separate integration.
The ecosystem should not depend on one operator
Shipped under a permissive OSI-approved licence, with every dependency checked for compatible redistribution and for operating the code as a network service. No strong copyleft anywhere in the dependency path.
Fork it
Run the whole facilitator yourself, on either network, with your own fee policy or none.
Embed it
Self-facilitate inside your own resource server when you would rather not run a second service.
Upstream
The Stellar upto network spec and its implementation go to the x402 repository, not into a private fork.
From the docs to a paid, discoverable endpoint
The target is well under an hour, from a clean machine, following the guide.