x402 payment facilitator — verifies and settles EIP-3009 micropayments multichain. v2 facilitator.
SaferSkills independently audited x402-facilitator (Agent Skill) and scored it 100/100 (green). The audit ran 55 deterministic rules across Security, Supply Chain, Maintenance, Transparency, and Community; it found 0 high-severity and 0 lower-severity findings. The full rule-by-rule trace and per-finding evidence are below. Free, methodology-open.
Findings & checks · 0 flagged
Every scanned point with the score it earned and what moved between them.
First recorded scan — no prior version to compare against.
The primary manifest — the file an agent reads to learn what this artifact does.
Verify and settle x402 v2 micropayments (USDC) on EVM chains. Powers https://three.ws/pay.
Live endpoint: https://facilitator.three.ws
| Chain | Network | USDC address |
|---|---|---|
| Base | eip155:8453 | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| Arbitrum | eip155:42161 | 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 |
| Ethereum | eip155:1 | 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 |
git clone https://github.com/nirholas/x402-facilitator
cd x402-facilitator
cp .env.example .env
# Set FACILITATOR_PRIVATE_KEY and fund it with ETH on each chain
npm install
npm run dev| Method | Endpoint | Description |
|---|---|---|
| GET | /health | Liveness + chain connectivity |
| GET | /info | Facilitator metadata |
| GET | /supported | Supported payment kinds |
| POST | /verify | Verify EIP-3009 signature off-chain |
| POST | /settle | Settle payment on-chain |
| GET | /balances | Gas + USDC balances per chain |
| GET | /fees | Estimated settlement cost |
| GET | /status/:txHash | Transaction status |
| GET | /.well-known/x402 | x402 discovery |
{
"x402Version": 2,
"scheme": "exact",
"network": "eip155:8453",
"payload": {
"signature": "0x...",
"authorization": {
"from": "0x<payer>",
"to": "0x<payTo>",
"value": "1000",
"validAfter": "0",
"validBefore": "1234567890",
"nonce": "0x<32 random bytes>"
}
}
}Deploy to Railway — set FACILITATOR_PRIVATE_KEY and fund the address with ETH on Base, Arbitrum, and Ethereum for gas. Add custom domain facilitator.three.ws.
three.ws — AI agent infrastructure
~30 seconds. Free. No account. Every finding cites a rule and a line of evidence.