The Payment Layer for AI.

Scale your x402 payments with institutional-grade compliance and reliability.

// ONE-LINE INTEGRATION

Monetize your API in minutes. Here's all it takes. (The facilitator URL ends in .xyz)

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

app.use(payTo, routes, {
  url: "https://facilitator.heurist.xyz"
})

Reliability and Compliance, Built for Scale.

High-Throughput

Scale with confidence. Our transaction management system is built for high-frequency requests.

Multi-Network Support

Address a global audience. One endpoint, multiple ecosystems.

OFAC Compliant

Meet regulatory requirements. Our facilitator automatically screens and blocks transactions from OFAC-sanctioned addresses.

API Free

Eliminate onboarding friction. Integrate in seconds with no API key needed.

Real-Time Observability

Track your onchain revenue with a real-time dashboard to monitor API health, transaction volume, and earnings. (Coming Soon)

Auto-Buyback

Accrue value without intervention. Automatically convert USDC revenue into your native project token on every settlement. (Coming Soon)

Start Building

Start accepting agentic crypto payments in minutes.

Chain

Framework

Payout wallet (payTo)

Install commands

npm i express x402-express

Sample server code

Express (x402-express) · Base (USDC)

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

const app = express();

// Monetize a route with x402. No API keys needed for the Heurist facilitator.
app.use(
  paymentMiddleware(
    "0xYourReceivingAddress",
    {
      "GET /api/paid": {
        price: "$0.01",
        network: "base",
        config: { description: "Paid endpoint (USDC)" }
      }
    },
    { url: "https://facilitator.heurist.xyz" }
  )
);

app.get("/api/paid", (req, res) => res.json({ ok: true, ts: Date.now() }));
app.listen(3000, () => console.log("http://localhost:3000"));

The x402 flow: server replies 402 with accepted options ⇒ client retries with X-PAYMENT (base64 JSON) ⇒ server verifies via /verify, settles via /settle, then returns 200. See the seller quickstart and set the facilitator URL to https://facilitator.heurist.xyz.