Optimistic rollup

Published:

An optimistic rollup is a Layer 2 scaling solution designed to increase the transaction throughput and reduce fees on a base blockchain, often referred to as Layer 1 (like Ethereum). The core idea is to process the majority of transactions off the main chain, thereby alleviating congestion on Layer 1. These rollups are termed “optimistic” because they assume that all transactions bundled and submitted to the main chain are valid by default. This approach significantly speeds up processing and lowers costs.

In practical blockchain software development, optimistic rollups bundle many transactions together into a single batch and submit a compressed summary of this batch to the main chain instead of executing each transaction individually on Layer 1. While transactions are assumed valid, there’s a “challenge period” during which anyone can dispute a potentially fraudulent transaction by submitting a “fraud proof.” If a fraud proof is successfully verified, the incorrect transaction (and any subsequent transactions in that batch) are reverted, and the party that submitted the fraudulent transaction is typically penalized.

Follow us on Facebook and LinkedIn to keep abreast of our latest news and articles

Other definitions

Crypto glossarymore-content
Oraclemore-content
Ommer block (Uncle block)more-content
On-ramp / Off-rampmore-content
Soft forkmore-content
Cryptomore-content