Function Selector & Event Topic

Compute the 4-byte function selector or 32-byte event topic from a human-readable signature. Extremely useful when analyzing raw transaction data and logs.

Signature → Hashes

Signature (human readable)

Function Selector (4 bytes)

0xa9059cbb

Event Topic (32 bytes)

0xa9059cbb2ab09eb219583f4a59a5d0623ade346d962bcd4e46b11da047c9049b

Examples: transfer(address,uint256), Approval(address,address,uint256), Swap(address,uint256,uint256,uint256,uint256,address)

Function Selector & Event Topic

Signature → Hashes

Tools