Nava Gateway developer overview
Developer Preview
The preview places a Nava Guardian policy verdict between normal x402 verification and merchant settlement for EIP-3009 USDC on Base or Base Sepolia. The facilitator submits the transfer and sponsors its ETH gas only after the payment has passed the applicable gates.
Integrate the Nava Gateway Developer Preview into this x402 payment flow. Preserve the existing verifier, require an approved Nava Guardian result before settlement, keep payer credentials out of logs, and fail closed on timeout, malformed response, or missing verdict.Choose a path
Use paymentGate or createResourceGate to protect a Fastify resource through the facilitator preview.
Use withGuardian(theirVerify, config) around your existing x402 verifier.
Shared primitive
Both integration paths use verifyPayment({ paymentPayload, paymentRequirements }, config). It maps signed authorization fields into a
preview PaymentAction, submits that action to Guardian, polls within a bounded
attempt count, and returns a normalized GuardianResult. It does not settle a
payment.
Use the verdict's outcome as the policy decision. Do not create a local
allowlist of reasonCode values; surface unknown codes and the accompanying
human reason so newer Guardian responses remain diagnosable.
Security-first checklist
- Treat the payer-scoped Guardian key as a bearer secret.
- Keep it out of URLs, logs, errors, analytics, and stored payment transcripts.
- Use the verdict's
outcome, not a localreasonCodeallowlist, as the policy decision. - Read the payment lifecycle and security and limitations before experimenting.