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Ethereum EIP-191 Signature Verifier
x402
Ethereum EIP-191 Signature Verifier is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).
Verifies an Ethereum EIP-191 personal signature, recovers the signer address, and checks it against an expected signer address.
Price / call$0.003
Success—
StatusUnknown
How this service works
Verifies crypto transactions and returns validation results.
Output
Returns the recovered Ethereum address derived from the EIP-191 signature, plus a boolean or explicit match result indicating whether the recovered address equals the expected signer address provided in the request.
Example use cases
Wallet ownership verification for login
“A user just signed the message 'Authenticate to my dapp nonce:99283' with their MetaMask and gave me signature 0x3fa8...b21c — please verify it was signed by 0xDead...Beef and confirm whether the signer matches.”
Smart contract call authorization check
“Before I process this transaction request, verify that the authorization message 'Approve transfer #42 for 500 USDC' was signed by the expected treasury wallet 0x1234...5678 — the signature they provided is 0xa1b2...c3d4.”
Off-chain governance vote authentication
“We received a governance vote submission with message 'Vote YES on proposal 7' and signature 0xdeadbeef...cafe — can you recover the signer address and check if it matches delegate wallet 0x9999...0000?”
Technical details
Endpoint
POSThttps://payai.agentstools.dev/crypto/verifyWhen to prefer
Choose this endpoint when you need to cryptographically verify an EIP-191 personal_sign Ethereum signature in a lightweight API call without running a local Ethereum node or web3 library. Ideal for agents handling wallet-based authentication, off-chain authorization checks, or governance vote validation where recovering the signer address and confirming it matches an expected wallet is the primary goal.
Side effects
- Invalid or malformed signature hex returns an error or null recovered address
- Mismatched message content causes a valid but unexpected signer address to be returned (match=false)
- Incorrect expected signer address format (non-checksummed or invalid hex) may cause validation errors
- Signature produced with a different signing standard (e.g. EIP-712 typed data instead of EIP-191) will return wrong recovered address
- Empty or missing required fields (message, signature) result in a 400-level error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| scheme | string | eip191 personal_sign or eip712 typed-data |
| message | — | Plain text / 0x-hex (eip191) OR a full typed-data object with types/domain/primaryType/message (eip712) |
| signature | string | 0x 65-byte signature |
| expected_signer | string | Optional address to compare the recovered signer against |
Tags
x402
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