Results for “Calldata vs Blob”

Calldata

Calldata is the input data attached to an Ethereum transaction or contract call: which function to run and with what arguments. It is recorded as part of the transaction, so anyone can read it on a block explorer.

What it means for you. Calldata is what you actually authorize when you sign: an approval or transfer is encoded in it, including the receiving address and amount. A wallet that shows only a string of hex is asking you to sign without seeing this; a decoded view reveals which function is called and with what values.

Sources: ethereum.org: Transactions, EIP-2028: Transaction data gas cost reduction, ethereum.org: Danksharding · checked 4 October 2026

Blob

A blob is a large chunk of data, about 128 KB, that can be attached to an Ethereum block through a special transaction type. Layer 2 rollups use blobs to publish their transaction data cheaply, and the network deletes the data after about 18 days.

What it means for you. Blobs are a large part of why layer 2 networks can charge low fees, but blob space has its own price that rises with demand, so layer 2 fees can climb when many rollups compete for it. Because blob data is pruned after roughly 18 days, it is not a permanent on-chain record.

Sources: EIP-4844: Shard blob transactions, ethereum.org: Danksharding · checked 4 October 2026