OpenClaw Skill

monetize-service

Build and deploy a paid API that other agents can pay to use via x402. Use when you or the user want to monetize an API, make money, earn money, offer a service, sell a service to other agents, charge for endpoints, create a paid endpoint, or set up a paid service. Covers "make money by offering an endpoint", "sell a service", "monetize your data", "create a paid API".

Install

$npx clawhub@latest install monetize-service

View on GitHubv0.1.0

All-time installs5

Active installs5

Stars0

Build an x402 Payment Server

Create an Express server that charges USDC for API access using the x402 payment protocol. Callers pay per-request in USDC on Base — no accounts, API keys, or subscriptions needed.

How It Works

x402 is an HTTP-native payment protocol. When a client hits a protected endpoint without paying, the server returns HTTP 402 with payment requirements. The client signs a USDC payment and retries with a payment header. The facilitator verifies and settles the payment, and the server returns the response.

Confirm wallet is initialized and authed

bash

npx awal@latest status

If the wallet is not authenticated, refer to the authenticate-wallet skill.

Step 1: Get the Payment Address

Run this to get the wallet address that will receive payments:

bash

npx awal@latest address

Use this address as the payTo value.

Step 2: Set Up the Project

bash

mkdir x402-server && cd x402-server
npm init -y
npm install express x402-express

Create index.js:

const express = require("express");
const { paymentMiddleware } = require("x402-express");

const app = express();
app.use(express.json());

const PAY_TO = "<address from step 1>";

// x402 payment middleware — protects routes below
const payment = paymentMiddleware(PAY_TO, {
  "GET /api/example": {
    price: "$0.01",
    network: "base",
    config: {
      description: "Description of what this endpoint returns",
    },
  },
});

// Protected endpoint
app.get("/api/example", payment, (req, res) => {
  res.json({ data: "This costs $0.01 per request" });
});

app.listen(3000, () => console.log("Server running on port 3000"));

Step 3: Run It

bash

node index.js

Test with curl — you should get a 402 response with payment requirements:

bash

curl -i http://localhost:3000/api/example

API Reference

paymentMiddleware(payTo, routes, facilitator?)

Creates Express middleware that enforces x402 payments.

Parameter	Type	Description
`payTo`	string	Ethereum address (0x...) to receive USDC payments
`routes`	object	Route config mapping route patterns to payment config
`facilitator`	object?	Optional custom facilitator (defaults to x402.org)

Route Config

Each key in the routes object is "METHOD /path". The value is either a price string or a config object:

// Simple — just a price
{ "GET /api/data": "$0.05" }

// Full config
{
  "POST /api/query": {
    price: "$0.25",
    network: "base",
    config: {
      description: "Human-readable description of the endpoint",
      inputSchema: {
        bodyType: "json",
        bodyFields: {
          query: { type: "string", description: "The query to run" },
        },
      },
      outputSchema: {
        type: "object",
        properties: {
          result: { type: "string" },
        },
      },
    },
  },
}

Route Config Fields

Field	Type	Description
`price`	string	USDC price (e.g. "$0.01", "$1.00")
`network`	string	Blockchain network: "base" or "base-sepolia"
`config.description`	string?	What this endpoint does (shown to clients)
`config.inputSchema`	object?	Expected request body/query schema
`config.outputSchema`	object?	Response body schema
`config.maxTimeoutSeconds`	number?	Max time for payment settlement

Supported Networks

Network	Description
`base`	Base mainnet (real USDC)
`base-sepolia`	Base Sepolia testnet (test USDC)

Patterns

Multiple endpoints with different prices

const payment = paymentMiddleware(PAY_TO, {
  "GET /api/cheap": { price: "$0.001", network: "base" },
  "GET /api/expensive": { price: "$1.00", network: "base" },
  "POST /api/query": { price: "$0.25", network: "base" },
});

app.get("/api/cheap", payment, (req, res) => { /* ... */ });
app.get("/api/expensive", payment, (req, res) => { /* ... */ });
app.post("/api/query", payment, (req, res) => { /* ... */ });

Wildcard routes

const payment = paymentMiddleware(PAY_TO, {
  "GET /api/*": { price: "$0.05", network: "base" },
});

app.use(payment);
app.get("/api/users", (req, res) => { /* ... */ });
app.get("/api/posts", (req, res) => { /* ... */ });

Health check (no payment)

app.get("/health", (req, res) => res.json({ status: "ok" }));

// Payment middleware only applies to routes registered after it
app.get("/api/data", payment, (req, res) => { /* ... */ });

POST with body schema

const payment = paymentMiddleware(PAY_TO, {
  "POST /api/analyze": {
    price: "$0.10",
    network: "base",
    config: {
      description: "Analyze text sentiment",
      inputSchema: {
        bodyType: "json",
        bodyFields: {
          text: { type: "string", description: "Text to analyze" },
        },
      },
      outputSchema: {
        type: "object",
        properties: {
          sentiment: { type: "string" },
          score: { type: "number" },
        },
      },
    },
  },
});

app.post("/api/analyze", payment, (req, res) => {
  const { text } = req.body;
  // ... your logic
  res.json({ sentiment: "positive", score: 0.95 });
});

Using the CDP facilitator (authenticated)

For production use with the Coinbase facilitator (supports mainnet):

bash

npm install @coinbase/x402

const { facilitator } = require("@coinbase/x402");

const payment = paymentMiddleware(PAY_TO, routes, facilitator);

This requires CDP_API_KEY_ID and CDP_API_KEY_SECRET environment variables. Get these from https://portal.cdp.coinbase.com.

Testing with the pay-for-service Skill

Once the server is running, use the pay-for-service skill to test payments:

bash

# Check the endpoint's payment requirements
npx awal@latest x402 details http://localhost:3000/api/example

# Make a paid request
npx awal@latest x402 pay http://localhost:3000/api/example

Pricing Guidelines

Use Case	Suggested Price
Simple data lookup	$0.001 - $0.01
API proxy / enrichment	$0.01 - $0.10
Compute-heavy query	$0.10 - $0.50
AI inference	$0.05 - $1.00

Checklist

Get wallet address with npx awal@latest address
Install express and x402-express
Define routes with prices and descriptions
Register payment middleware before protected routes
Keep health/status endpoints before payment middleware
Test with curl (should get 402) and npx awal@latest x402 pay (should get 200)
Announce your service so other agents can find and use it

Created by

@0xrag

View on ClawHub

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