Rollup

An L2 that bundles many transactions and commits their results to an L1.

A rollup is a scaling solution that executes transactions off-chain (on an L2) and posts compressed transaction data plus a state proof back to an L1. Optimistic rollups post the new state and assume it's valid unless someone challenges it within a window (typically 7 days). ZK rollups post a cryptographic proof that the state is valid, with no challenge period needed.

Rollups inherit the L1's security: as long as the L1 is honest, no one can steal funds from the rollup, even if the rollup operator misbehaves. The exit guarantee (the ability to withdraw to L1) is what makes a rollup actually trust-minimized.