Optimistic vs ZK Rollups
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Upgrade to ProRollups batch transactions off-chain and post data back to L1. Two types: Optimistic Rollups (Arbitrum, Optimism) assume transactions are valid and allow a challenge period (~7 days) for fraud proofs. If someone proves fraud, the invalid batch is reverted. They're EVM-compatible and easier to build. ZK Rollups (zkSync, Scroll) generate mathematical proofs of validity for each batch. No challenge period needed — withdrawals are instant once the proof is verified. ZK Rollups are more complex but offer faster finality and potentially better scalability.
💡 Key Takeaway
This lesson covers the fundamental concepts. Make sure you understand these before moving to the next chapter.