Blockchain
Rollup
A Layer 2 scaling solution that bundles many transactions into a single transaction settled on Layer 1.
Last Updated
2026-03-19
Related Concepts
What is Rollup?
A rollup is a Layer 2 scaling solution that batches hundreds of transactions and settles them as a single entry on Layer 1. It delivers faster and cheaper transactions while inheriting the security of the underlying mainnet.
How does Rollup work?
- Users send transactions to the rollup network instead of directly to Ethereum.
- A sequencer executes them off-chain and compresses them into a single batch.
- The batch is submitted to a Layer 1 smart contract with a summary of the new state.
- Optimistic rollups assume validity unless fraud is proven; ZK rollups include a cryptographic proof with every batch.
Why does Rollup matter?
Rollups are Ethereum's primary scaling strategy, enabling web-scale throughput without sacrificing decentralization or security.
Key features of Rollup
- Dramatically lower fees than Layer 1
- Full EVM compatibility
- Two variants: Optimistic (fraud proofs) and ZK (validity proofs)
- Inherits Layer 1 security guarantees
Examples of Rollup
Arbitrum and Optimism handle billions in assets as optimistic rollups. zkSync and Starknet use ZK proofs for faster finality. Swapping on a rollup costs under 0.10 dollars versus 10 dollars or more on mainnet.