An open-source x402 payment facilitator for Stellar with native resource discovery.
Servers charge per request in stablecoins without running chain infrastructure. Agents pay without holding XLM.
facilitator: running on testnet/discovery: designed, not yet built/Apache-2.0
The problem
Three gaps sit between an API that could be sold per request and a client that could buy it.
Card rails have minimums and merchant accounts that make a fraction of a cent meaningless. Accepting crypto instead means running keys, nodes and fee management — infrastructure that has nothing to do with the product.
An autonomous client needs a funded wallet and native gas before it can buy anything. For software that spins up for one task and disappears, that bootstrapping problem is the whole obstacle.
There is no index of what is for sale. An agent can only buy from services it was already told about, which caps the market at whatever a human wired up in advance.
How it works
HTTP 402 has been reserved for payment since 1997. Turnpike is the toll booth that makes it mean something: it verifies the payment, settles it on Stellar, and pays the network fee so the buyer does not have to.
An ordinary GET, with no payment attached. The client is unmodified — the conformance suite uses wrapFetchWithPayment straight from the public @x402/fetch package.
Terms travel in the PAYMENT-REQUIRED header: the scheme, the network, the SEP-41 token contract, the amount in atomic units, and the address to pay. The facilitator's fee-sponsorship posture rides along in the same block.
GET /supportedNot a blank cheque. The entry binds the token contract, the amount and the recipient, so the signature authorises exactly one transfer and nothing else. The client needs no XLM: it never pays a network fee.
Verification simulates the transfer and checks the authorization — right asset, right amount, right recipient, signed by the payer, not expired. Settlement submits it with Turnpike's own account as the transaction source, so Turnpike pays the network fee.
POST /verifyPOST /settle200, the thing the client asked for, and a PAYMENT-RESPONSE header carrying the transaction hash. Roughly twenty seconds end to end, most of it waiting for the ledger to close.
There are no custom smart contracts in Turnpike. Settlement runs through the Stellar Asset Contract that already exists on-chain, and every cryptographic operation — authorization-entry validation, transaction assembly, submission — belongs to the Apache-2.0 @x402/stellar package. Turnpike is the HTTP surface, the error mapping and the account that pays the fee.
Proof
These are settled transactions on Stellar testnet, not screenshots. Open any of them on a block explorer and check the amount, the ledger, and which account paid the fee.
A scheduled probe keeps paying on testnet, so the running totals move daily and are not kept here. The current snapshot — payments made, payments failed, and every failure analysed — lives in the README and in the raw CI artifacts behind it. Yes, there has been a failure; it is written up in full.
What exists, and what doesn't
A payment facilitator that overstates itself is worse than useless, because the first thing anyone does is test it. So: this is the line, precisely.
Quickstart
One command, from nothing. It creates and funds testnet accounts through Friendbot, brings the facilitator and a demo resource server up with Docker, then makes a stock x402 client pay for real and prints the transaction hash.
$ git clone https://github.com/Turnpike-org/turnpike
$ cd turnpike
$ ./demo.shNo faucet visit, no wallet, no shared secret — the default payment asset is the native XLM Stellar Asset Contract precisely so a stranger can reproduce this unattended. Needs Node 22.12+ and Docker. Two to four minutes, most of it building images.