Optimism vs zkSync: Contract Porting Risk

Full EVM Opcode Support: Runs all EVM opcodes natively, including complex ones like SELFDESTRUCT. This means near-zero code modifications for most contracts. This matters for porting complex, battle-tested DeFi protocols like Aave or Compound with minimal audit overhead.

Custom ZK-Circuit VM (zkEVM): Uses a custom virtual machine compiled to zero-knowledge circuits. This can require minor Solidity refactoring for precompiles (e.g., cryptographic functions) and certain opcodes. This matters for teams prioritizing the long-term security and scalability benefits of ZK proofs over immediate porting ease.

Multi-Round Fraud Proofs (Cannon): Uses a dispute resolution game with a 7-day challenge window. While introducing a trust assumption for fast withdrawals, the model is battle-tested with $6B+ TVL across OP Mainnet, Base, and other chains. This matters for risk-averse protocols where a mature, audited security model is non-negotiable.

Validity Proofs (ZK-SNARKs): Every state transition is verified on Ethereum L1 with a cryptographic proof, providing Ethereum-level security for finality. No need for external watchers or challenge periods. This matters for financial applications where the strongest possible trust minimization is required for every single block.

Near-perfect compatibility: Uses the standard EVM, requiring minimal to no code changes for most contracts. This matters for rapid deployment of existing dApps like Uniswap V3 or Aave V3, which ported in weeks.

Sequencer centralization: Most OP Stack chains rely on a single, permissioned sequencer for transaction ordering and L1 submission. This matters for protocols requiring maximal censorship resistance, as it introduces a potential single point of failure.

Built-in AA: zkSync's LLVM compiler natively supports EIP-4337 account abstraction, enabling gasless transactions and social recovery out-of-the-box. This matters for building superior UX-focused applications like wallets (Argent) or subscription services.

zkEVM divergence: Uses a custom zk-friendly VM (zkEVM) and compiler (LLVM), which can break hardhat/forge plugins and require audit for edge-case behavior. This matters for complex DeFi protocols with intricate math (e.g., yield vaults) where subtle VM differences can introduce risk.

Near-perfect compatibility: Uses the OVM, which is functionally identical to the EVM. This means contracts deploy with zero or minimal code changes. This matters for complex, battle-tested DeFi protocols like Uniswap or Aave, where a single bytecode discrepancy can break core logic.

Security model dependency: Relies on a 7-day challenge period for fraud proofs, requiring active watchdogs. This introduces a withdrawal delay risk for users and means your protocol's finality inherits this vulnerability. This matters for high-value financial applications where capital efficiency and instant finality are non-negotiable.

Built-in AA at L1: Offers native account abstraction (ERC-4337) without requiring separate smart contract wallets, enabling gasless transactions and social recovery. Combined with Validity Proofs (ZK), it provides Ethereum-level security with ~1 hour finality. This matters for mass-market dApps prioritizing user experience and cryptographic safety.

Bytecode-level differences: zkEVM is not fully equivalent; it's a transpiled environment. Certain precompiles (e.g., SHA256), assembly code, and some opcodes require adaptation or are unsupported. This matters for protocols with heavy reliance on complex cryptography or low-level optimizations, increasing audit scope and porting time.