> For the complete documentation index, see [llms.txt](https://docs.etherscale.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.etherscale.xyz/core-concepts/overview-of-rollups/optimistic-rollups.md).

# Optimistic Rollups

Optimistic Rollups process transactions off-chain and post the transaction data on-chain without immediate verification. They assume transactions are valid (hence "optimistic") and only verify them if challenged. This approach significantly reduces gas fees and increases throughput while still leveraging Ethereum's security through fraud proofs.

Read more on Optimistic rollups <https://blog.etherscale.xyz/what-are-optimistic-rollups-a328f62173cb>

<figure><img src="/files/L2DkfNP8Zrw9xFVXbohR" alt=""><figcaption><p>Optimistic Rollup</p></figcaption></figure>