What are Based Rollups?

What is a Based Rollup?

A based rollup is a Layer 2 scaling solution where transaction sequencing is handled by the Layer 1 blockchain, like Ethereum. It uses Ethereum’s existing infrastructure (e.g. searchers, builders, and proposers) to process and include rollup blocks within Ethereum’s block production, removing the need for separate L2 sequencers.

This design simplifies operations, reduces costs and improves security by directly inheriting Ethereum’s decentralization and liveness guarantees. It avoids the complexity and overhead of standalone sequencers while economically benefiting Ethereum through the flow of maximal extractable value (MEV) back to the base layer.

The trade off is reduced flexibility in sequencing, making features like fast pre-confirmations harder to implement. Despite this, the simplicity and strong alignment with Ethereum’s infrastructure make based rollups an efficient and decentralized scaling solution.

‍

How Do Based Rollups Work?

Here’s a technical breakdown of how based rollups embed their transaction sequencing into the Layer 1 blockchain, utilizing its infrastructure for bundling, sequencing, and validation:

• Transaction Bundling: Layer 2 searchers gather transactions from users and organize them into efficient bundles.
• Block Assembly: L1 searchers and builders sequence these bundles into complete Layer 2 blocks, ready for integration.
• Integration with L1: L2 blocks are included within Ethereum’s L1 bundles and passed to L1 block builders for processing.
• Validation and Finality: Ethereum validators confirm the L1 blocks containing the L2 data, finalizing transactions with the same security guarantees as L1 activities.

‍

Based Rollup Examples

Several projects are actively implementing based rollup architectures, leveraging Layer 1 (L1) infrastructure for sequencing and security:

• Taiko: An Ethereum-equivalent rollup designed as a fully decentralized, configurable system supporting zk-rollup and optimistic rollup models while relying on L1 for transaction sequencing.
• Espresso Systems: Focuses on decentralized sequencing frameworks, aligning with the Based Rollup model to ensure secure and efficient block production.
• Fairblock: Implements permissionless sequencing, leveraging Ethereum’s L1 to process and finalize Layer 2 transactions.
• Sorella: Utilizes based rollup principles to integrate L1 consensus and data availability layers, reducing reliance on external sequencers.

These projects exemplify how Based Rollups harness L1 infrastructure to deliver scalability, security, and decentralization in Layer 2 solutions.

‍

Based Rollups vs. Other Rollups

Based rollups rely on Ethereum’s Layer 1 for transaction sequencing, enhancing decentralization and inheriting its security and liveness. In contrast, other rollups (e.g. optimistic or zk rollups) use standalone sequencers, often centralized, which can introduce risks of downtime and censorship.

Economically, based rollups align with Ethereum by directing maximal extractable value (MEV) to Layer 1, while other rollups capture MEV at Layer 2 for operational incentives. However, based rollups are constrained by Ethereum’s scalability limits, whereas other rollups offer more flexibility and faster finality through custom mechanisms.

The trade-off is clear: based rollups maximize decentralization and operational simplicity, while other rollups prioritize scalability and operational control.

‍

Bottom line

Based Rollups provide a technically elegant scaling solution by embedding transaction sequencing directly into Ethereum’s Layer 1 infrastructure. 

This design enhances security, decentralization, and efficiency by eliminating the need for standalone sequencers while aligning economically with Ethereum through MEV redistribution. 

Though they sacrifice some flexibility in sequencing, the simplicity and strong integration with Ethereum make Based Rollups a robust choice for developers focused on decentralization and secure scalability.