# 402\-mcp enables x402 payments in MCP

**Published:** September 12, 2025 | **Authors:** Ethan Niser

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Introducing [`x402-mcp`](https://github.com/ethanniser/x402-mcp), a library that integrates with the AI SDK to bring [x402](https://www.x402.org/) paywalls to Model Context Protocol (MCP) servers to let agents discover and call pay for MCP tools easily and securely.

With x402-mcp, you can define MCP servers with `paidTools` that require payment to run, enabling account-less, low-latency, anonymous payments directly in AI workflows. Payments confirm in ~100–200ms, with fees under $0.01 and support for minimums under $0.001.

Getting started is easy, here's how you can define a paid tool:

```tsx
import { createPaidMcpHandler } from "x402-mcp";
import z from "zod";
const handler = createPaidMcpHandler(
  (server) => {
    server.paidTool(
      "add_numbers",
      { 
        // declare a price of $0.001
        price: 0.001 
      },
      { a: z.number(), b: z.number() },
      async (args) => {
        // ...your tool call
      }
    );
  },
  { recipient: process.env.WALLET_ADDRESS }
);
export { handler as GET, handler as POST };
```

And integrating with AI SDK MCP Clients takes just one function to enable payments:

```tsx
import { experimental_createMCPClient as createMCPClient } from "ai";
import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";
import { withPayment } from "x402-mcp";
const mcpClient = await createMCPClient({
  transport: new StreamableHTTPClientTransport(url),
}).then((client) => withPayment(client, { account: process.env.PRIVATE_KEY }));
const tools = await mcpClient.tools();
```

Read more about [x402](https://vercel.com/blog/introducing-x402-mcp-open-protocol-payments-for-mcp-tools) or try our full stack [x402 AI Starter Kit](https://x402-ai-starter.vercel.app/).

**x402 AI Starter**
Fullstack AI demo of x402 with Next.js, AI SDK, AI Gateway, AI Elements and the Coinbase CDP
[Deploy](https://vercel.com/templates/ai/x402-ai-starter)

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📚 **More updates:** [View all changelog entries](/changelog/sitemap.md) | [Blog](/blog/sitemap.md)