Solidity Event Hash Calculator
Calculate keccak256 hashes for Solidity event signatures. Get topic 0 values for filtering Ethereum logs.
Common Solidity Events
Indexed vs Non-Indexed Parameters
In Solidity events, parameters marked as indexed are stored in log topics (topics[1], topics[2], topics[3]), while non-indexed parameters are ABI-encoded in the log data field.
Topics are searchable, so indexed parameters can be used to filter logs efficiently. Ethereum allows a maximum of 3 indexed parameters per event (plus topics[0] which is always the event signature hash).
Note: Anonymous events do not include the signature hash in topics[0], allowing them to have up to 4 indexed parameters.
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