x402 MCP server: pay x402 APIs from your agent in 2026

What is an x402 MCP server?

It is an MCP server that gives your agent tools to find paid HTTP APIs and pay their 402 challenges. An x402 seller answers an unpaid request with HTTP 402 and a price, and only returns data after a signed payment. MPP sellers send a similar challenge under the Machine Payments Protocol. A coding agent with no way to pay stops at the 402.

There are two kinds. Some servers pay from a USDC wallet your agent controls, so you fund and secure that wallet. Others pay the seller for you and charge a balance you funded by card, so the agent never holds crypto. Locus Pro is the second kind.

• What is x402?
• What is the Machine Payments Protocol?

Which x402 MCP servers work in Claude Code, Cursor and Codex?

All of these reach x402 sellers from a coding agent. They differ in who holds the money and who signs the payment. Details checked November 10, 2026.

Which one should you choose?

Pick by whether you want to hold crypto, and by how many sellers you need.

• Choose Locus Pro if you want no crypto at all, one balance for x402 and MPP sellers and for key-based APIs such as Perplexity or Brave, and a price ceiling on every call.
• Choose Locus Pro Enterprise if your product's agents call paid APIs on behalf of your customers and you want to bill each customer per call.
• Choose AgentCash if you already hold USDC and want your agent to pay x402 and MPP sellers from a wallet on your machine.
• Choose PayAPI Market if you want free search over many x402 listings and your client can already pay a 402.
• Choose the Coinbase Bazaar MCP if you build your own agent on the MCP SDK and want CDP-managed wallets.
• Choose the seller's own endpoint if you only need one API and your agent already holds USDC on that seller's network.

How does Locus Pro pay x402 and MPP sellers from credits?

Your agent uses the same Locus tools for every API. search finds an endpoint and shows its price and payment rail. describe returns the input schema, the price, and who receives the data. execute runs the call: Locus pays the seller over x402 or MPP and charges your credits. By default, 1,000 credits equal $1.

Seller listings are labeled. Exa's official x402 search, for example, is listed as an x402 seller Locus has not reviewed, so Locus cannot promise it stays available. Pass max_credits on execute as a ceiling. A call priced above it is declined before it runs, and nothing is charged.

What does an x402 or MPP call cost through Locus Pro?

These are live Locus Pro catalog prices for seller listings that Locus pays over x402 or MPP. Locus has not reviewed these four sellers, so it cannot promise they stay available. Prices checked November 10, 2026.

When should your agent pay sellers with its own USDC?

When it already holds USDC on the seller's network and you can protect the key. The agent pays the seller's own price, with no account and no API key. Tavily, for example, sells search at x402.tavily.com, and its docs say refunds for upstream failures go back to the wallet that paid.

The costs are operational. AgentCash stores private keys in plain text under ~/.agentcash, and anyone with them can spend the USDC. You fund each network you need, each seller sets its own price, and any spending limit lives in your client.

Use credits instead when you do not want to hold crypto, when you also need APIs that only sell to key holders, or when you want one ledger and spend caps across every call.

How do you connect Locus Pro in Claude Code, Cursor or Codex?

Add the hosted MCP server once and sign in with OAuth. The URL is the same in every client: https://api.paywithlocus.com/api/credits/mcp.

• Claude Code: run claude mcp add --transport http locus-pro https://api.paywithlocus.com/api/credits/mcp, then run /mcp, pick locus-pro, and choose Authenticate.
• Cursor: add a locus-pro entry with that url under mcpServers in ~/.cursor/mcp.json, then enable it in Cursor's MCP settings and approve Locus in your browser.
• Codex: run codex mcp add locus-pro --url https://api.paywithlocus.com/api/credits/mcp, then codex mcp login locus-pro.
• Then ask your agent to find an x402 search API in Locus, show its price, and run it with a max_credits ceiling.

• Add Locus to Claude Code
• Add Locus to Cursor
• Add Locus to Codex

Can a platform pay x402 sellers for its own customers?

Yes, and that is the main way companies use Locus Pro. On an Enterprise workspace, your server calls the catalog with your Locus key and names the customer on each call with the X-Locus-End-User header.

Locus checks that customer's credit balance before the call runs, pays the seller, and charges the catalog price plus the margin you set. Your customers never hold crypto or provider keys, and the ledger shows every charge per customer.