Rollup Architecture & L2 Engineering

How optimistic and ZK rollups are actually built. Sequencers, DA layers, bridge contracts, fraud proofs, force-inclusion windows.

5 lessons · 3 hr 45 min · expert

1. 1Rollup Anatomy: Sequencer, Prover, BridgeThe three structural components of every rollup and the data flow that ties them together — from L2 transaction submission, through batching and L1 posting, to bridge state updates.35 min
2. 2Optimistic Rollups: Fraud Proofs & Withdrawal WindowsHow Arbitrum BoLD and Optimism Cannon turn the 7-day challenge window into real security, the math behind the window length, and why the Superchain ate L2 mindshare from 2023 onward.35 min
3. 3ZK Rollups: Validity Proofs & Prover NetworksHow zkSync Era, StarkNet, Linea, Scroll, Polygon zkEVM, and Taiko prove L2 execution correct in a single L1 transaction — and what prover hardware actually costs to run.35 min
4. 4Data Availability: Calldata, EIP-4844, Celestia, EigenDAWhy DA is the bottleneck for L2 economics, how EIP-4844 blobs collapsed L2 fees in March 2024, and what Celestia, EigenDA, and Avail bring as alternative DA layers.30 min
5. 5Force Inclusion & Censorship ResistanceThe L1 deposit queue, sequencer-bypass timers, escape hatches, and the L2BEAT Stage 0/1/2 classification that distinguishes a real rollup from a multisig with a marketing budget.25 min

Educational only — not financial advice.