Optimistic vs ZK Rollups: Data Compression

Leverages Ethereum as a data availability layer: Posts all transaction data as cheap calldata to L1. This provides strong security but with lower compression ratios (~10-100x). Ideal for general-purpose dApps like Arbitrum and Optimism, where developer familiarity and moderate fees are prioritized over maximal compression.

EVM-equivalent architecture: Chains like Arbitrum Nitro and Optimism Bedrock minimize dev tooling changes. Faster time-to-market for protocols migrating from Ethereum, as they don't require complex ZK circuit development. This matters for teams with existing Solidity codebases aiming for rapid deployment.

Achieves superior compression via validity proofs: Only posts a tiny cryptographic proof (~1 KB) to L1, with optional data availability solutions. Enables ~100-1000x compression, drastically reducing L1 data fees. Critical for high-throughput, fee-sensitive applications like decentralized exchanges (e.g., dYdX, Loopring) and payments.

Provides cryptographic security guarantees upon proof verification on L1 (~10 min), versus the 7-day fraud proof window in Optimistic Rollups. Eliminates withdrawal delays, enabling capital-efficient bridges. This is essential for financial primitives requiring strong, fast settlement assurances, such as perp DEXs and institutional DeFi.

Lower fixed compute overhead: No complex proof generation means cheaper transaction costs for users. This matters for high-volume, low-value applications like gaming or social feeds where every cent counts. Platforms like Arbitrum One and Optimism leverage this to offer sub-$0.01 fees during normal operation.

Seamless developer experience: Full compatibility with Ethereum's EVM and tooling (Solidity, Hardhat, Foundry). This matters for rapid protocol migration and deployment where developer hours are the primary cost. Teams can port dApps from Ethereum Mainnet to Arbitrum or Base with minimal code changes.

7-day challenge window for withdrawals: Users and protocols must wait for state finality when bridging to L1. This matters for high-frequency trading or instant settlement use cases where capital efficiency is critical. Solutions like Across Protocol and Hop Exchange offer fast bridges, but add trust assumptions and cost.

Instant L1 state verification: Validity proofs provide immediate finality, enabling trustless, near-instant withdrawals. This matters for exchanges and payment rails where security and speed are non-negotiable. zkSync Era and Starknet use STARK/SNARK proofs to settle in minutes, not days.

Smaller calldata footprint: Complex transactions are compressed into tiny proofs, reducing L1 data posting costs at scale. This matters for privacy-focused apps or complex logic where on-chain data minimization is a feature. Scroll and Polygon zkEVM achieve up to 90%+ reduction in gas costs versus optimistic counterparts for certain operations.

High fixed operational cost: Running specialized provers requires significant hardware (GPU/ASIC) and expertise. This matters for smaller projects or general-purpose dApps where the cost and complexity of proof generation can be prohibitive, potentially leading to centralization in prover networks.

Leverages Ethereum's full data availability: Posts all transaction data (calldata) to L1, relying on fraud proofs for security. This provides ~10-100x cost savings versus L1 by batching transactions. Ideal for general-purpose dApps like Uniswap or Aave where ultimate cost predictability is key. The trade-off is a 7-day withdrawal delay for security challenges.

Near-perfect compatibility with Ethereum's execution environment. Protocols like Arbitrum Nitro and Optimism Bedrock can run unmodified Solidity/Vyper smart contracts. This drastically reduces migration friction for developers, making it the best choice for rapid ecosystem growth and porting existing DeFi protocols without complex rewrites.

Validium & zkEVM models compress data off-chain: Only a tiny cryptographic proof (ZK-SNARK/STARK) is posted to L1. This enables extreme scalability (2,000-9,000 TPS) and near-instant finality (minutes vs. days). Critical for high-frequency trading (dYdX v3) and payment-focused applications where speed and finality are non-negotiable.

Validity proofs provide mathematical security: State transitions are verified, not disputed. This eliminates the need for a challenge period, enabling trustless, instant withdrawals. The architecture is inherently resistant to censorship and MEV extraction, making it superior for bridges and institutional finance where capital efficiency is paramount.