All projects on Base matching “eip-3009”

Offline pre-sign check (no RPC, fast): decodes a transaction, EIP-712 typed data (Permit, Permit2, EIP-3009), an EIP-7702 authorization or an x402 402 + payment payload and returns SAFE/CAUTION/DANGER, every risk flag with its reason, decoded args, counterparties, x402 payment-vs-402 match and OFAC SDN screening. Use /v1/check for on-chain facts and simulation.

Check whether a Base transaction settled x402 payments (USDC transferWithAuthorization, EIP-3009): for each, the payer, the payTo address, the amount in USDC, the authorization nonce, the facilitator that sent it, and the seller behind the payTo address from Bazaar listings (origins and 30-day payers).

Did this Base payment settle? Status, block, timestamp and confirmations for one transaction hash, with its ERC-20 Transfers decoded (token, from, to, amount; up to 100 listed, transfers_total gives the full count) and any EIP-3009 authorization used, plus match flags for an optional expected payTo and amount, so an x402 PAYMENT-RESPONSE can be checked. Required: hash. $0.002 USDC on Base. Transac

Verify a claimed USDC payment on Base: given a tx hash (or an x402 PAYMENT-RESPONSE header) and what you expect (payee, payer, amount, time window, confirmations), reads the chain and returns match / mismatch / not_settled / not_found with per-field checks, finality, the x402 EIP-3009 pattern, a self-payment flag and a second-RPC cross-check. Cannot show who owns an address or that a service was d

Ownership verification with a signed receipt. The receipt is the product: the same answer is available for free at /api/verify-ownership.