Package deal

Another way to reduce costs is to bundle transactions. You can think of this as gift giving. On the blockchain, each transaction is an individual gift, put in a different box. This can lead to very high shipping costs because you need to pay a shipping fee for each gift you send. Rollups, on the other hand, put many gifts in one big box and pay for the shipping once, splitting the shipping cost for each gift.

If you want to explain it in more technical language, it is that rollups package raw transaction data into calldata. The verification method of Rollup transactions is different from that of transactions on the chain. The transaction data is packaged only to store the data on the underlying blockchain. The verification nodes or rollup participants can rebuild the state of the Layer 2 network at any time if necessary. However, the core logic remains unchanged, that is, multiple rollup transactions are stored in one packaged transaction on the main chain.

This can effectively reduce transaction costs and clear the way for blockchain expansion. Compressing data can further reduce transaction execution costs.

Zk-rollups and optimistic rollups package transactions in the same way.