Settlement
EIP-3009
EIP-3009, Transfer With Authorization, defines a signed message that lets another address submit an ERC-20 transfer. The holder signs from, to, value, a validity window, and a nonce. USDC implements it. In x402, that signature is how a buyer authorizes USDC without broadcasting the transaction.
Explanation
The EIP specifies transferWithAuthorization and the typed data the wallet signs. A relayer, here the facilitator, pays the network fee and submits the signature. The token contract checks the signature, the time window, and that the nonce has not been used. Circle's Gateway docs tell integrators to sign the same EIP-3009 type, with USDC's 6 decimals, when they authorize a nanopayment.
The x402 version 2 spec names eip3009 as an asset transfer method on the EVM exact scheme, next to permit2. The method is a detail of how the authorization was formed. The chain log this index stores is still the resulting transfer. EIP-3009 is also an EOA signature checked with ordinary public-key recovery. Circle documents that Gateway nanopayments do not accept ERC-1271 smart-contract signatures on this path.
Live data
Related terms
Sources
- EIP-3009: Transfer With Authorization — Ethereum Improvement Proposals
- x402 Protocol Specification, version 2 — Coinbase x402
- Sign EIP-3009 payment authorizations — Circle
- Nanopayments — Circle