Gateway receives payment
The buyer attaches a PAYMENT-SIGNATURE header. The gateway forwards the signed authorization to the facilitator — buyers never call the facilitator directly.
Verify and settle on-chainpayments for the gateway
The facilitator validates signed payment authorizations and submits settlement transactions. Gateway processes call /verify and /settle over HTTP — buyers never talk to the facilitator directly.
Workflow
Where the facilitator sits in the stack
After a buyer attaches a PAYMENT-SIGNATURE header, the gateway asks the facilitator to verify and settle before proxying to upstream.
Verify authorization
The facilitator validates the signature, scheme, network, asset, and amount against the gateway's x402 accept options via POST /verify.
Settle on-chain
After verification succeeds, the facilitator submits the settlement transaction on-chain via POST /settle and returns the transaction hash.
Proxy upstream
The gateway retries the buyer request with proof of settlement, then proxies the response from your upstream API unchanged.
Capabilities
Settlement infrastructure for every gateway
Hosted testnet for development, self-hosted deployment for production, and dashboard visibility into verify and settle traffic.
Verify endpoint
Validate signed payment authorizations before any on-chain work. Gateway processes call /verify with the buyer's PAYMENT-SIGNATURE payload.
On-chain settlement
Submit exact and batch-settlement transactions on supported networks. Returns transaction hashes the gateway can attach to retried requests.
Supported capabilities
Discover networks, schemes, and x402 versions from GET /supported. Match gateway endpoint accepts to what your facilitator can settle.
Hosted testnet
AxLabs runs a development facilitator on Base Sepolia and Neo X Testnet — point FACILITATOR_BASE_URL at the testnet URL to start integrating.
Self-hosted option
Deploy ax402-facilitator or the local Compose stack when you need your own settlement infrastructure and key management.
Request visibility
The seller dashboard logs verify and settle events per gateway hostname — filter by type, result, and time window.
Hosted testnet
AxLabs development facilitator
A hosted testnet facilitator is available for development and staging. Match endpoint accepts to the facilitator /supported response.
FACILITATOR_BASE_URL=https://ax402.testnet.app.mf.axlabs.net
curl -s https://ax402.testnet.app.mf.axlabs.net/health
curl -s https://ax402.testnet.app.mf.axlabs.net/supported | jq .Supported networks include Base Sepolia and Neo X Testnet with exact and batch-settlement schemes, as returned by the facilitator supported endpoint.
Documentation
Go deeper in the facilitator guide
Stack role, testnet setup, self-hosted deployment, and control-plane configuration are documented for sellers.
Use the hosted stack or bring your own facilitator
Start on the AxLabs testnet facilitator for development, then self-host when you need your own settlement infrastructure.