zkEVM Architecture: Polygon zkEVM vs zkSync Era Compared

Frequently Asked Questions

01.What is a zkEVM and how does it differ from a standard ZK rollup?

A zkEVM is a zero-knowledge rollup that generates validity proofs for the full Ethereum Virtual Machine instruction set, allowing existing Solidity contracts to deploy without rewriting. A standard ZK rollup proves only a custom instruction set optimized for specific operations like token transfers. The key distinction is EVM equivalence: a zkEVM accepts unmodified bytecode and produces a validity proof that Ethereum mainnet verifies on-chain, while a custom ZK rollup requires developers to recompile or rewrite their applications for a different virtual machine architecture.

02.How do Polygon zkEVM and zkSync Era differ in their circuit design approach?

Polygon zkEVM uses a SNARK-based proof system built on PIL, Polynomial Identity Language, and a custom arithmetization layer called the zkASM, which translates EVM opcodes into polynomial constraints. zkSync Era uses an LLVM-based compiler toolchain called zksolc that compiles Solidity and Vyper into a custom intermediate representation before generating STARK proofs wrapped in a Groth16 SNARK for on-chain verification. Polygon prioritizes bytecode-level EVM equivalence at Type 2. zkSync Era optimizes for prover throughput at Type 4 equivalence, accepting minor EVM behavioral differences in exchange for faster proof generation at scale.

03.Which zkEVM should a production team choose in early 2024, Polygon zkEVM or zkSync Era?

Teams porting existing Ethereum mainnet contracts with minimal code changes should prefer Polygon zkEVM, as its Type 2 equivalence level means standard Hardhat and Foundry tooling works without modification and gas costs closely mirror mainnet. Teams building net-new applications and prioritizing throughput, native account abstraction via EIP-712 paymasters, or sequencer customization should favor zkSync Era, which offers faster proof finality at scale and a more flexible developer experience through its LLVM toolchain, at the cost of needing to verify EVM behavioral edge cases before deployment.