Meter quickstart

Charge for an Express endpoint per request. You need Node 20+, an Express app and a Stellar address to be paid at. You do not need to run a node, hold XLM, or create an account with us.

1. Install

bash

npm i @reinkey/meter

The packages are pre-release. Until they are on npm, build them from the monorepo: pnpm build && pnpm pack in packages/meter.

2. Meter an endpoint

TypeScript

import express from "express";
import { reinkey } from "@reinkey/meter";

const rk = await reinkey({
  facilitator: process.env.REINKEY_API,   // the facilitator that verifies vouchers
  payTo: process.env.SELLER_ADDRESS,      // your Stellar address (G…)
});

const app = express();

app.get(
  "/book",
  rk.meter({ price: 5000n, unit: "request", description: "Order book" }),
  (req, res) => res.json({ bids: [], asks: [] }),
);

app.listen(8080);

The testnet facilitator is https://reinkey.onrender.com. price is in USDC base units: 5000n is 0.0005 USDC.

3. See the 402

bash

curl -i localhost:8080/book

HTTP

HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: eyJ4NDAyVmVyc2lvbiI6Mi…

The JSON body repeats the terms so an agent can act on them: scheme channel, the network, the asset, your payTo, the amount and unit, and the channel contract to open a channel on.

4. Get paid

Any x402 client that speaks the channel scheme can now pay you. With the Reinkey SDK:

TypeScript

import { x402Fetch } from "@reinkey/sdk";

const { res, receipt } = await x402Fetch("http://localhost:8080/book", { signer, network });

See the Reins quickstart for how signer is created. Inside your handler the verified receipt is on req.payment.

5. Settlement

You don't have to do anything. The facilitator claims on your behalf once the unclaimed amount on a channel passes its threshold, and always before a channel expires. Funds arrive at payTo in USDC.

To settle right now, call POST $REINKEY_API/channels/:id/claim. Anyone may call it; it can only pay the channel's payee.