ABI Encoder
Build calldata from a signature and a JSON argument list.
Runs offline
Enter a signature and a JSON argument array to build calldata.
About abi encoder
Encoding is what turns a human-readable call into the hex a contract actually receives: four bytes of selector followed by each argument padded into thirty-two byte words. Useful for building a multisig transaction by hand, testing against a node, or checking that an interface is sending what it claims. Large integers need quoting as strings — JSON numbers silently lose precision above 2⁵³, which is far below a typical token amount.
Common questions
How do I encode ABI calldata from a function signature?
Enter the signature and a JSON list of arguments. This builds the selector and the argument words the EVM expects, which is what wallets put in the data field of a call.
Does encoding calldata send a transaction?
No. Encoding only produces hex. Broadcasting still needs a wallet, a network fee, and your signature. Treat the output as unfinished input until you have verified the arguments against what you intend to call.
What argument types are supported?
Common ABI types for ordinary calls — addresses, integers, bools, bytes and arrays in JSON form. If a type fails to encode, the error is shown rather than silently producing calldata that would revert on chain.