Ethereum utilities that run in your browser.
Converters, key tools, signers, ABI codecs and live chain reads for Ethereum, Optimism and Arbitrum. Every call goes straight from your browser to a public RPC (or your own). Nothing is logged here.
Tip: the whole site caches itself on your first visit. For key generation or signing, you may want to turn off the internet once the footer says "safe to go offline" — every tool keeps working.
Convert & Hash
Units, hex, bytes, keccak, checksums.Unit Converter
offlineConvert between wei, gwei, ether and any token decimals with exact big-integer math.
Hex / Bytes Converter
offlineHex ↔ decimal ↔ UTF-8 ↔ bytes ↔ base64, with padding and RLP helpers.
Keccak-256 & Selectors
offlineHash text or bytes with keccak256 / sha256, compute function & event selectors, ENS namehash.
Address Checksum
offlineValidate and EIP-55 checksum addresses, compute CREATE / CREATE2 addresses.
Keys & Wallets
Generate and inspect keys — all in your browser.Sign & Verify
EIP-191 / EIP-712 signatures, recovery.Sign Message
keysEIP-191 personal_sign with a local key or your browser wallet.
Sign Typed Data
keysEIP-712 typed data: inspect domain separator, struct hash and digest, then sign.
Verify / Recover Signature
offlineRecover the signer of an EIP-191 message or EIP-712 payload and verify against an address.
ABI & Transactions
Encode, decode, build, inspect.ABI Encoder / Decoder
offlineEncode function calls and decode calldata / return data from a human-readable or JSON ABI.
Calldata Decoder
offlinePaste raw calldata — the selector is looked up in public signature databases and decoded.
Raw Transaction Decoder
offlineDecode a signed raw transaction (legacy, 2930, 1559, 4844, 7702) and recover its sender.
Offline Transaction Builder
keysBuild an EIP-1559 transaction, sign it offline with a local key, get the raw hex — optionally broadcast.
Chain Data
Live reads via public RPC — no backend.Address / Tx / Block Lookup
rpcBalance, nonce, code and transactions across Ethereum, Optimism and Arbitrum at once.
Gas Tracker
rpcLive base fee, priority fee percentiles and fee history for all supported chains.
ENS Resolver
rpcResolve names to addresses, reverse-resolve addresses, fetch avatars and text records.
Contract Reader
rpcCall any view/pure function with an ABI (auto-fetched from Sourcify when verified).
ERC-20 Token Inspector
rpcName, symbol, decimals, supply and balances for any ERC-20 token.