EIP-712 Inspector & Signature Verifier

Inspect typed-data fields, reproduce EIP-712 hashes, and optionally recover a signer without connecting a wallet or sending data anywhere.

Local inspection with no wallet connection

Typed data, signatures, addresses, and calculated hashes remain in this browser. The tool makes no RPC call and does not send these values to analytics.

EIP-712 typed-data JSON

65-byte signature (optional)

Expected signer address (optional)

Reproduce what an EIP-712 signature authorizes

EIP-712 combines a domain separator with a hash of a typed message. This inspector parses those inputs, displays the canonical primary type, and calculates each hash with the maintained ethers implementation. An optional signature can recover the authorizing EVM address.

Web3 inspection guides

How to Read EIP-712 Typed Data Before You Sign How to Decode EVM Calldata and Spot Token Approvals How Solana Transactions Are Structured: Legacy vs Versioned

How to inspect typed data before signing

Paste the complete typed-data JSON or load the official Mail example.
Optionally add a 65-byte signature and expected signer, then run the local inspection.
Review the domain, spender and amount fields, timestamps, hashes, and signer result without treating any single result as a safety verdict.

Deterministic inspection has strict limits

The tool does not query contract code, token balances, nonces, revocation state, protocol reputation, or chain state. Timestamps are compared with the browser's current Unix time, and the far-future label uses a fixed 365-day threshold. Unknown application semantics remain unknown.

Related Web3 tools

Crypto Address Validator Ethereum Unit Converter Base58 Encoder / Decoder

Frequently asked questions

Does a recovered signer prove a request is safe?: No. Recovery proves which key signed the calculated digest, not whether the resulting authorization is desirable or trustworthy.
Why inspect chainId and verifyingContract?: They help bind a signature domain to a chain and verifying contract. When absent, that domain separation is less specific.
Does EIP-712 stop replay attacks?: No. Replay handling depends on the application, often through nonces, deadlines, or state tracked by the verifying contract.
Are typed data and signatures uploaded?: No. Inspection and signature recovery run locally in the browser without RPC calls or wallet connections.

EIP-712 Inspector & Signature Verifier

Inspect typed-data fields, reproduce EIP-712 hashes, and optionally recover a signer without connecting a wallet or sending data anywhere.

Local inspection with no wallet connection

Typed data, signatures, addresses, and calculated hashes remain in this browser. The tool makes no RPC call and does not send these values to analytics.

Frequently asked questions

Does a recovered signer prove a request is safe?

No. Recovery proves which key signed the calculated digest, not whether the resulting authorization is desirable or trustworthy.

Why inspect chainId and verifyingContract?

They help bind a signature domain to a chain and verifying contract. When absent, that domain separation is less specific.

Does EIP-712 stop replay attacks?

No. Replay handling depends on the application, often through nonces, deadlines, or state tracked by the verifying contract.

Are typed data and signatures uploaded?

No. Inspection and signature recovery run locally in the browser without RPC calls or wallet connections.