Solidity ABI Encoder

ABI (Application Binary Interface) encoding converts function calls into the byte format the EVM expects. The first 4 bytes are the function selector — the first 4 bytes of Keccak-256(functionSignature). Parameters are then ABI-encoded: each static type padded to 32 bytes, dynamic types (string, bytes) using offset/length/data.

This tool encodes function selectors and basic types. It uses SHA-256 for the selector as an approximation; production code should use ethers.js or web3.js for correct Keccak-256 and full ABI support.

The function signature is the function name and parameter types, e.g., transfer(address,uint256) or balanceOf(address). No spaces, no parameter names. The selector is derived from this string. Enter the exact signature — transfer(address,uint256) not transfer(address, uint256) — to match Solidity's encoding.

address: 40 hex chars, with or without 0x. uint256: decimal integer. bool: true or false. string: UTF-8 text. bytes32: up to 64 hex chars. For arrays and structs, use a full ABI library. This tool covers the most common types for simple contract interactions.