MERCHANTS / FOR DEVELOPERSx402 · Base USDC

Put your API
behind a paywall.

Set your payout wallet, price, and route once. Add one line of middleware, then deploy your service.

OPEN SELLER DASHBOARD ↗LIST ON SONAR ↗
MERCHANT SETUP GUIDE

Copy the checklist into your agent or developer workspace.

VIEW MERCHANT SKILL.MD ↗
01 / INITIALIZE

Describe your
paid route.

The setup command creates your config and a private signing key. Never commit the key file.

npx @seedhape/x402-merchant-sdk init

Enter your Base payout address. The price and route can be changed later in seedhape.config.json.

02 / ADD ONE LINE

Mount the
paywall.

Install the SDK and Express, then use the middleware generated in your project.

npm install @seedhape/x402-merchant-sdk express

import express from "express";
import { paywall } from "./seedhape.config.mjs";

const app = express();
app.use(paywall); // protects the route and settles payment
app.get("/api/weather", (req, res) => res.json({ temperature: 24 }));
03 / DEPLOY

Keep keys
on your server.

Set your public HTTPS origin and facilitator URL in the server environment. Store the generated key file as a deployment secret.

Required setup

PUBLIC_ORIGINYour public HTTPS origin, used for signed checkout details.
FACILITATOR_URLOptional override for payment verification and settlement.
.seedhape/merchant-keys.jsonPrivate signing key; keep it out of source control.

Key maintenance

keys:rotateActivate a fresh signing key.
keys:jwksPrint the public keys for your JWKS endpoint.
ERC-7710 configView Seedhape's public facilitator settings ↗
DISCOVERY

Help agents
find the service.

List your deployed endpoint on Sonar with its price, description, and input details. Discovery helps agents find the service; the paywall still verifies and settles each purchase.

OPEN SONAR ↗READ THE X402 SELLER GUIDE ↗