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The b402 Facilitator is the official off-chain service that powers payment verification and settlement for the b402 protocol. It provides shared infrastructure for verifying signed payment payloads, executing on-chain settlements, and ensuring consistent behavior across networks and token schemes. By abstracting blockchain complexity, the facilitator offers a uniform API for developers and resource servers—enabling better reliability, observability, and interoperability across multiple merchants and applications.
Official b402 Facilitator endpoint: https://facilitator.b402.ai

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Key Benefits

  • Unified verification and settlement: Consistent handling of all supported schemes and networks.
  • Reduced on-chain complexity: Offload blockchain operations from individual servers.
  • Multi-tenant design: Serve multiple merchants or applications through a common /verify and /settle API.
  • Service discovery: Help clients identify compatible merchants via the /list endpoint.

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Facilitator Responsibilities

The facilitator is responsible for securely mediating between clients (buyers) and resource servers (sellers) while ensuring correct on-chain behavior.
  • Expose secure /verify and /settle endpoints following x402-compatible request/response formats
  • Validate Payment Payloads according to scheme and network specifications
  • Prevent replay attacks and ensure idempotent verification
  • Submit verified transactions for on-chain settlement and monitor confirmations
  • Provide clear, structured error responses for failed verifications or settlements
  • Maintain reliable RPC and wallet infrastructure for supported networks
  • Implement logging, metrics, rate limiting, and alerting for operational robustness