The b402 Facilitator is the official off-chain service that powers payment verification and settlement for the b402 protocol.
Endpoint: https://facilitatorv3.b402.ai
What It Does
The Facilitator bridges HTTP requests and on-chain settlement. It:
- Verifies signed payment payloads (EIP-712 or UserOp)
- Settles payments on-chain via the Relayer contract
- Deploys smart wallets on first use
- Executes private token swaps
- Processes private (Incognito) payments via the b402 privacy pool
Developers never interact with the blockchain directly. The Facilitator handles gas fees, transaction submission, and confirmation monitoring.
Supported Payment Models
| Model | Flow | Gas |
|---|
| EOA | Sign EIP-712 → verify → settle | Facilitator pays gas |
| Smart Wallet | Build UserOp → sign → settle via bundler | Paymaster covers gas (deducted from payment) |
| Incognito | Shielded payment with b402 privacy pool | Facilitator pays gas |
Key Benefits
- Non-custodial. The Facilitator never holds funds. Payments are signed by the buyer and settled directly on-chain.
- Gasless for users. Gas costs are absorbed by the Facilitator (EOA) or deducted from the payment token (Smart Wallet).
- Idempotent verification. Replay attacks are prevented via nonces and on-chain checks.
Endpoints
The Facilitator exposes these endpoint groups:
| Group | Purpose | Auth |
|---|
| Health | Service status | None |
| EOA Payments | Verify and settle EOA payments | None |
| Smart Wallet | Verify and settle smart wallet payments | None |
| Wallet Deployment | Deploy and manage smart wallets | None |
| Incognito | Private payments via privacy pool | None |
Security
- Signature verification. Every payment is cryptographically verified before settlement.
- On-chain finality. Payments are only confirmed after on-chain transaction confirmation.
- No private key exposure. Buyers sign locally; the Facilitator only receives signatures.
- Nonce-based replay protection. Each payment uses a unique nonce to prevent double-spending.
