List your API

1 · Make your endpoint payable

Add x402 middleware in front of the route you want to charge for. It answers unpaid requests with 402 and verifies payment headers on paid ones — your handler code stays untouched.

import express from "express";
import { paymentMiddleware } from "x402-express";

const app = express();

app.use(
  paymentMiddleware("0xYourReceivingAddress", {
    "/api/search": {
      price: "$0.005",
      network: "base",
      config: {
        description: "Web search returning the top 10 results as JSON",
      },
    },
  })
);

app.get("/api/search", handler); // now costs $0.005/call

Middleware packages exist for Express, Hono, Next.js, FastAPI, Flask, and Gin — see the x402 repo.

2 · Register with the discovery network

Listings come from the x402 Bazaar — the discovery layer this directory indexes. Services using the Coinbase facilitator are discoverable automatically once they set discoverable: true in their payment config. You can also register explicitly via the Bazaar docs.

3 · Stand out in the directory

• Write a real description. Listings with clear one-sentence descriptions get categorized correctly and rank in search. Say what the endpoint returns, not just what it is.
• Declare input and output schemas. Bazaar metadata with example inputs and outputs powers the code samples and example responses on your listing page.
• Set a service name and icon. Named services with icons are grouped under a provider profile with all your other endpoints.
• Price honestly. The directory sorts by price and shows 30-day usage. Competitive per-call pricing plus real traffic is what earns the top spots.