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The 4Mica payment flow keeps HTTP simple while moving settlement complexity into signed guarantees, facilitator calls, clearing cycles, and protocol enforcement.

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Sequence

  1. A payer deposits ETH or a supported into the Core4Mica vault.
  2. A seller protects an HTTP route with x402 payment requirements.
  3. The buyer receives HTTP 402, signs a guarantee with a unique request ID, and retries the request.
  4. The seller verifies and settles the payment through the facilitator, then serves the protected response.
  5. Payable guarantees enter a clearing cycle. Net debtors pay their positions, while defaults are covered from locked collateral according to protocol rules.

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Protocol flow

The synchronous HTTP flow ends when the resource returns the protected response. Validation, clearing, net settlement, default coverage, and withdrawal handling continue asynchronously.

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Headers

  • V1 payment payloads commonly travel as X-PAYMENT.
  • V2 payment payloads commonly travel as PAYMENT-SIGNATURE.
  • Both bind claims such as request ID, amount, recipient, asset, timestamp, and version.
  • The server should verify and settle before serving protected content.

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Actors

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Guards and guarantees

  • /verify performs preflight validation without issuing a guarantee.
  • /settle submits the signed request to Core and returns a BLS certificate.
  • Every guarantee uses a unique req_id; Core rejects a duplicate identity.
  • V1 guarantees become FINALIZED_PAYABLE after issuance.
  • V2 guarantees remain PENDING_VALIDATION until finalized, disputed, cancelled, or resolved through the validation path.
  • Only FINALIZED_PAYABLE guarantees enter clearing-cycle netting.
  • Settlement and finality timing are deployment configuration values.
  • Withdrawals remain subject to open guarantees, clearing obligations, and the configured grace period.

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Settlement Outcomes

  • Settled: the guarantee is included in a clearing cycle and its net position is paid.
  • Default remunerated: locked collateral covers an unpaid net position.
  • Cancelled or disputed: the guarantee stays out of netting and collateral follows the applicable resolution path.
  • Invalid: verification or validation failed and the resource should not be served as paid.
See transaction lifecycle for the full V1 and V2 state model.