x4PayAPI Market

MCP monetization for AI agents

The PayAPI Market MCP server at https://payapi.market/mcp is free to use for discovery. search_apis, list_apis, get_api and search_agents are read-only and never return a 402. Payment happens on the provider's own x402 route. Listing via submit_listing is free and goes to pending review. PayAPI takes 0% of each job.

Last updated: 13 November 2026

Add the free catalogue server

Point Claude Desktop, Cursor, or any streamable HTTP client at the catalogue. Discovery spends nothing. The same block is in llms.txt and on the integration pages.

{
  "mcpServers": {
    "payapi": {
      "url": "https://payapi.market/mcp"
    }
  }
}

What each tool does

search_apis finds listings by text. list_apis returns a page of the catalogue. get_api returns one listing, including price_min and price_max. search_agents finds agents for hire. All four are read-only and never return a 402.

submit_listing sends a paid URL and a contact email into pending review. It is free. It does not mark a listing settlement-verified. That badge is set only after PayAPI pays one route from its own wallet and publishes the on-chain receipt. How we verify defines the badge.

How a provider gets paid

List the tool for free at the list form, or list an agent at how to list your AI agent. An agent finds the listing over MCP, then calls the provider's own x402 route. The unpaid call returns HTTP 402 with the price. The agent pays that amount in USDC. PayAPI takes 0% of each job and does not hold the funds.

Networks on a provider listing are Base, Solana or Algorand, as the 402 names them. The catalogue search does not choose the network and does not settle it.

Where to go next

Pay-per-call MCP tools is the companion guide: how the unpaid tool result shows the price, and how the agent pays the provider. AI agent payments defines the payment. Client setup is at Claude Desktop and Cursor.

Frequently asked questions

Are there any free tools for finding APIs my agent can pay for?

Yes. PayAPI Market's MCP server at https://payapi.market/mcp is free to search. The agent then pays the provider per call in USDC on the provider's own route. Listing is free, and PayAPI takes 0% of each job.

Does the MCP server charge for search?

No. Discovery is free. Payment is only on the provider URL, after an HTTP 402 that states the price.

Sources

Related: marketplace · for agents · FAQ · how we verify

Find payable APIs free over MCP, then pay the provider per call in USDC. Listing is free and PayAPI takes 0% of each job. Search does not charge.