AgentSmith Facilitator
The AgentSmith Facilitator implements the open-source x402 v2 protocol for fee-sponsored payments on Stellar Testnet and Mainnet. It verifies buyer-signed Soroban authorization entries, builds and submits the transaction, waits for confirmation, and returns the settlement result to the resource server. It never holds the buyer's payment funds.
The default exact payment path is built with the official @x402/core and @x402/stellar packages and follows the normative requirements of the x402 v2 protocol and the official Stellar exact scheme. The optional upto path is an experimental AgentSmith extension, covered under Schemes below.
Building with an AI agent?
This entire reference is also published as one plain-text file at /llms.txt. Point a coding agent (Claude Code, Cursor, and similar) at it and it can scaffold and run a paying Seller or Buyer from the spec alone.
text
Read https://docs.agentsmith.xyz/llms.txt, then build and run a Node Seller
with one paid GET route on the AgentSmith testnet Facilitator, plus a
Buyer that pays it.Two ways to use it
Use the hosted Facilitator
AgentSmith runs it — point your Resource Server at the hosted URL. Testnet needs no key; mainnet needs an API key.
Environments & endpoints →Self-host your own
Run the whole Facilitator yourself, on either network, with your own fee policy or none.
Self-hosting guide →Non-custodial by design
The Facilitator never holds or sources the buyer's funds. The buyer's signature binds the asset, recipient and amount, so the Facilitator can build and submit the transaction and sponsor the XLM network fee, but it cannot redirect a payment or change what was authorized. For metered upto, the on-chain settlement Kernel moves the token directly from buyer to recipient and enforces the buyer's signed ceiling and validity window. The Kernel is intentionally minimal — no owner, upgrade, pause, withdrawal, or arbitrary-call interface — so it can neither divert nor custody funds.
Source code: the Facilitator and payment SDK are in agentsmith-oss, and the Soroban Kernel contracts in agentsmith-contracts. See Self-hosting to run your own.