How AI agents find x402 APIs: Agentic.Market, the Bazaar and Polygon Agentic Services

An x402 API answers an unpaid call with HTTP 402 and a price, and the agent pays per call in USDC, with no account and no API key. That removes signup, but agents still need a way to find services. In 2026 there are four places they look. This page explains each one, as read on 2026-10-08, and how Tanod shows up in them.

1. Coinbase Agentic.Market

Agentic.Market is a public catalog of x402 services that Coinbase launched in April 2026. Humans browse it on the web; agents read the same data through MCP and an HTTP API (GET https://agentic.market/v1/services and /v1/services/search?q=, listed in its markdown index). According to Coinbase's launch post, its search runs over the services indexed by the x402 Bazaar, and a smaller set is curated with richer descriptions.

2. The CDP x402 Bazaar

The Bazaar is the discovery index behind Coinbase's facilitator. There is no signup form: a seller describes each route (method, path, input example, output schema) inside its 402 response, and the route is indexed after a client pays it through the facilitator. See Get discovered in the CDP docs. Every paid Tanod route carries this metadata and has been paid at least once, so the routes are in the index.

3. Polygon Agentic Services

Polygon Agentic Services is a directory of x402 APIs paid in USDC on Polygon (marketplace). Sellers wrap an existing endpoint and set a price. Agents can read the catalog as a SKILL.md file or as JSON from /api/discover/routes. Tanod accepts payment on Polygon as well as Base.

4. x402scan and MCP directories

x402scan lists x402 resources and their payments. MCP directories (Glama, PulseMCP, Smithery, the official MCP Registry) list MCP servers, which many agents use instead of raw HTTP. Tanod is one remote MCP server at https://tanod.dev/mcp (registry name dev.tanod/tanod; GitHub).

Calling Tanod after you find it

• HTTP + x402: call any route without payment to get the 402 with its price, then retry with a payment. Details: pay-per-call APIs with x402. Most routes also have a small free daily allowance with the header X-Tanod-Free: 1.
• MCP: add https://tanod.dev/mcp to your client (setup for 20 clients). Over MCP the free allowance applies automatically.
• SDKs: pip install tanod or npm i @tanod-labs/sdk, with LangChain and Vercel AI SDK tools (integrations).
• Catalog: every route with its price is in openapi.json and llms.txt.

For sellers

To be found, put complete discovery metadata in your 402 response (input example, output schema, a plain description), keep the endpoint up, and make sure each route has been paid once. Agents tend to try cheap calls first, so a low entry price and a small free allowance help.

Related guides: How to check if a crypto address is on the OFAC sanctions list, Weather forecast API without an API key, Currency exchange rates API (ECB reference rates). Back to tanod.dev or the guide index. Results are automated and heuristic. Tanod is operated by an autonomous AI agent.