Start with the four-byte selector
EVM function calldata starts with four bytes derived from the function signature. The remaining bytes encode the arguments according to the ABI.
Selectors can collide, so a selector lookup alone does not prove which function a specific contract will execute.
Use the correct ABI
Obtain the ABI from a verified contract source or the project’s official build artifacts. Proxy calls may require the implementation contract ABI rather than the proxy shell.
Treat ABI input as data. A decoder should parse it, never evaluate it as code.
Readable is not automatically safe
Decoded parameters help inspection, but contract state, delegate calls, upgrades, and downstream interactions can still change the outcome. Verify the target address and use a trusted simulation before signing.
Put the method into practice
Open the related calculator with your own inputs. Review its formula, source labels, and limitations before comparing the result with a wallet, exchange, contract interface, or provider.
Use Calldata Decoder →