- Merchants receive payments into escrow and release funds after delivery
- Payers can request refunds, freeze payments, and submit evidence during disputes
- Arbiters verify transactions or resolve disputes (two models below)
Two Operator Models
Marketplace (deployMarketplaceOperator): The merchant releases funds after escrow. If the payer contests, they file a refund request and an arbiter resolves it. Use this for general commerce where most transactions are uncontested.
Delivery Protection (deployDeliveryProtectionOperator): The arbiter evaluates every transaction automatically and is the only address that can release funds. If the arbiter does not release, funds auto-refund after escrow. Use this for AI content verification, schema validation, or automated quality checks.
Packages
@x402r/sdk is the only package most developers need. It includes role-scoped client factories, 8 action groups (payment, escrow, refund, evidence, freeze, query, operator, watch), and an .extend() plugin system.
For low-level access to contract ABIs and deploy utilities:
Guides
Merchants
Deploy an operator, accept a payment, release funds from escrow.
Payers
Check payment state, request a refund, submit evidence.
Arbiters
Review disputes, approve or deny refunds, distribute fees.
Supported Chains
All contracts are deployed to identical addresses on every chain via CREATE3. Only USDC differs.| Chain | Chain ID | USDC |
|---|---|---|
| Base Sepolia | 84532 | 0x036CbD53842c5426634e7929541eC2318f3dCF7e |
| Ethereum Sepolia | 11155111 | 0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238 |
| Arbitrum Sepolia | 421614 | 0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d |
| Ethereum | 1 | 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 |
| Base | 8453 | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| Polygon | 137 | 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 |
| Arbitrum One | 42161 | 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 |
| Optimism | 10 | 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 |
| Celo | 42220 | 0xcebA9300f2b948710d2653dD7B07f33A8B32118C |
| Avalanche C-Chain | 43114 | 0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E |
| Monad | 143 | 0x754704Bc059F8C67012fEd69BC8A327a5aafb603 |
| Linea | 59144 | 0x176211869cA2b568f2A7D4EE941E073a821EE1ff |
| SKALE Base | 1187947933 | 0x85889c8c714505E0c94b30fcfcF64fE3Ac8FCb20 |