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How agents pay

Short lessons on how an AI agent pays for an API call over HTTP 402. Try local samples, compare the records, and check the cited sources.

No wallet, no sign-in, nothing to install. Protocol claims use the pinned x402 evidence baseline below; quotum behavior cites the docs.

quotum x402 per-request intake remains closed. Do not sign a per-request payment.

  1. 1The 402 handshakeDraft. Not available in this edition.
  2. 2Receipts and how to verify spendCompare a settlement response with the accepted offer, and separate a receipt hash from a verified spend figure.
  3. 3A cap is not a budgetDraft. Not available in this edition.
  4. 4Keys that cannot raise their own limitSeparate spending authority from limit management. This local model keeps a fixed total and does not let the spending key raise it.
  5. 5Retries and double paymentKeep the original payment, reconcile pending settlement, and check authorization expiry before considering a replacement.

Sources

  1. x402 evidence baseline, 3 November 2026. Version 2 specification at the pinned commit, EVM exact, ERC-3009.
  2. quotum receipts, seat keys and Pay as you go. Site copy captured 5 November 2026.

Written by the team that sells capped inference keys. Check the cited docs yourself.