A rollup is a popular type of Layer 2 scaling solution. It works by bundling, or rolling up, many transactions together and processing them off the base chain, then posting a compressed summary back to the Layer 1. This lets far more transactions be handled at lower cost.
There are two main families. Optimistic rollups assume transactions are valid by default and allow a window for anyone to challenge fraudulent ones. ZK rollups instead use cryptographic proofs to demonstrate that the bundled transactions are valid before they are accepted.
Each approach has trade-offs in speed, cost, and how quickly funds can be withdrawn to the base layer. For a beginner, the key idea is simply that rollups compress activity to scale a network while still leaning on the base chain for security. The finer details matter mainly as you go deeper.
Frequently Asked Questions
What is the difference between optimistic and ZK rollups?
Optimistic rollups assume transactions are valid and allow a challenge period, while ZK rollups use cryptographic proofs to demonstrate validity before transactions are accepted.
Why are rollups useful?
They bundle many transactions and process them off the base chain, posting a compressed summary back. This allows far more activity at lower cost while relying on the base layer for security.
