Calldata

Calldata is the immutable input data attached to a transaction that encodes which contract function to call and the ABI-encoded arguments it receives.

When a transaction targets a contract, its calldata carries a four-byte function selector followed by ABI-encoded arguments. The contract reads this input to dispatch to the right function and decode parameters. Calldata is read-only and cheaper than storage, which is why rollups compress it to cut costs. Raw calldata is opaque hex until decoded against the contract ABI. Our decoded transaction data resolves the selector and arguments into named fields, so you see the method and parameters directly instead of parsing raw input yourself.