⚡ Two Rollup Types: Optimistic vs ZK
Discover the trade-offs between fraud proofs and validity proofs
Scale Ethereum with Layer 2 rollup technology
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0 / 5 completed⚖️ Optimistic vs ZK Rollups
There are two main types of rollups: Optimistic and ZK (Zero-Knowledge). Both batch transactions off-chain, but they differ fundamentally in how they prove transaction validity to Ethereum.
🔄 Interactive Type Selector
Click each rollup type to explore their characteristics, trade-offs, and how they work.
How Optimistic Rollups Work
Proof Mechanism
Fraud Proofs
Core Assumption
Transactions are valid unless proven otherwise
Withdrawal Time
7 days (challenge period)
Technical Complexity
Lower
Proof Generation
Only when challenged
Transaction Cost
Cheaper
Ecosystem Maturity
More mature (Arbitrum, Optimism)
📋 Fraud Proof Process
- 1. Submit Transactions: Sequencer posts batch to Ethereum
- 2. Challenge Period: 7-day window for anyone to challenge
- 3. Fraud Proof: If invalid, challenger proves it on-chain
- 4. Penalize: Malicious sequencer loses stake, state reverts
⏱️ Withdrawal Speed Comparison
Adjust network congestion level and see how withdrawal times compare between rollup types.
50%
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Optimistic Rollup
3 days
Challenge period must pass before withdrawal
🟣
ZK Rollup
25 hours
Proof verified, withdrawals processed quickly
Why the difference? Optimistic rollups need time for fraud proofs. ZK rollups prove validity upfront, enabling instant finality.
⚔️ Head-to-Head Comparison
| Feature | Optimistic | ZK |
|---|---|---|
| Withdrawal Time | 7 days | Minutes |
| Transaction Cost | $0.10-0.25 | $0.25-0.50 |
| EVM Compatibility | Full (Arbitrum) | Partial (improving) |
| Proof Complexity | Lower | Higher |
| Finality | Probabilistic | Instant |
| Data Availability | On-chain | On-chain |
| Current Leaders | Arbitrum, Optimism | zkSync, StarkNet |
✅ Optimistic Advantages
- • Full EVM compatibility (easier migration)
- • Lower transaction costs
- • More mature ecosystem
- • Simpler to understand and audit
✅ ZK Advantages
- • Fast withdrawals (minutes vs days)
- • Stronger security guarantees
- • Better privacy potential
- • More scalable long-term