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The Agent Marketplace is a curated catalog of x402-compatible services that accept USDC. Every listing is screened (each seller’s payout wallet is continuously sanctions-checked) and continuously health-checked, so your agent finds services that are compliant and live. Buyers and sellers meet here. Buyers (AI agents) find services and pay per request, with no subscriptions, no accounts, and no API keys. Sellers (API owners) list a service once and get paid in USDC for each call. Browse the catalog at agents.circle.com/services, or query it programmatically with the Discovery API.

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Explore

Discovery API

Query the public catalog over one HTTP endpoint. Filter by network, price, payment rail, and protocol type. No API key.

Become a seller

Monetize your API by charging agents per request in USDC. Scaffold it in minutes with a Circle Skill.

Get listed

Submit your service for review. Once approved, it appears in the catalog and the Discovery API.

Browse the catalog

Explore 600+ live services across 15+ blockchain networks in your browser.

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How a paid request works

Every service in the catalog follows the same x402 handshake:
  1. An agent calls the service with no payment. The service responds 402 Payment Required, plus a machine-readable price list (the accepts array). Each entry states which token (asset), on which blockchain (network), how much (amount), and to which address (payTo).
  2. The agent’s wallet picks an option it can pay, signs a USDC payment, and retries the request with the signed payment attached.
  3. The service settles the payment and returns the real response.
No accounts, no API keys: the payment is the authentication.

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Why the Agent Marketplace

  • One integration, many blockchains: A single query returns services priced across 15+ networks. No per-chain registry hunting.
  • Curated, not scraped: Filter 600+ services by query, network, price, payment rail, and protocol type, instead of parsing thousands of raw endpoints.
  • Compliance built in: Each seller’s payout wallet is continuously sanctions-screened. Blocked sellers drop out, so you inherit a watchlist-clean catalog.
  • Agent-native responses: Each listing ships structured payment requirements plus input and output JSON Schema, so any wallet can construct and execute payment without a human reading docs.
  • Live, not stale: Endpoints are continuously health-checked, and unreachable ones are auto-excluded.
  • Standards-based: CAIP-2 networks, the x402 protocol, the x402 Bazaar discovery schema, and OpenAPI and A2A discovery surfaces. No API key, no account.