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Payments with x402

Updated 2026-10-07

How x402 works

x402 uses the HTTP status 402 Payment Required.

  1. You send a request without payment.
  2. The API answers 402 and states the price and how to pay.
  3. You pay the stated amount in USDC on Base.
  4. You send the same request again with the proof of payment, and receive the result.

Good to know

  • The price is known before you pay. It is part of the 402 answer.
  • There is no account, subscription or API key.
  • You are not charged for requests that fail before a result is produced. See errors.
  • Only ordinary wallets (EOA) can pay in this version. The signature is checked locally as an EIP-712 signature by the paying address; smart-contract wallets (ERC-1271 or ERC-6492 signatures) get a 402 that says so, and nothing is charged.
  • Prices per tool are on the pricing page. For several domains in one request, see bulk checks.