What exactly are "rollups"? I got asked this question on a recent space. Put simply: - rollups are chains - rollups can be appchains - a rollup is a Layer-2 (an L2, or even an L3) These words are often an interchangeable and synonymous way to describe a specific chain from a technical perspective. But what precisely are rollups then? To answer this, we first need to understand the make up of a blockchain, and specifically what a Layer-1 (L1) is in this case. L1s are primarily made up of three parts: 1) Consensus Mechanism: orders and validates transactions, e.g. proof-of-stake 2) Data Availability (DA) Layer: stores transaction data 3) Execution Environment: the place where transactions are processed and updated; smart contracts, account balances, the part that users directly transact on Rollups, or L2s, remove the Execution Environment from the L1 into its own separate layer - making it its own chain for the purposes of how users and developers interact with it. It then inherits and relies on Consensus from the L1 and, in some cases, DA from the L1 or leverages alternative-DA (e.g. Avail, Celesita, EigenDA). So, rollups are execution environments - rollups are chains - they run smart contracts and process transactions, hold account balances, connect to wallets, etc. They submit proofs or transaction batches to the L1 (usually Ethereum) to finalize and anchor the state of the chain. Why does this matter and why is it important? Because of this architecture, rollups can scale throughput, reduce fees, and stay secure by piggybacking on Ethereum’s consensus and different DA layers. TLDR: they're cheaper, faster, and more scaleable chains. It also enables companies, teams, devs, to more easily have dedicated and opinionated blockspace (e.g. their own chain) to offer the best possible UX. To wrap up, some example of rollups that you may know and even interact with daily are: - @base - Apechain @apecoin - @AbstractChain - @arbitrum - @unichain - @sophon - and many more that you can check out on @Calderaxyz's ecosystem portal At this point, we're seeing the blockchain and crypto space moving more and more towards a world with thousands of rollups where every company and application has their own chain. This world will be powered by Caldera. Gmera.