Glossary
zkEVM
A zero-knowledge virtual machine that executes Ethereum bytecode and produces a validity proof, letting a ZK rollup run existing EVM contracts while proving each state transition.
A zkEVM is a virtual machine that runs Ethereum EVM execution inside a zero-knowledge circuit, emitting a succinct proof that a batch of transactions was executed correctly. This lets a ZK rollup inherit Ethereum's tooling — Solidity contracts, wallets, and infrastructure — while settling to L1 with validity proofs instead of an optimistic challenge window.
zkEVMs are ranked by how closely they match Ethereum. Type 1 is fully consensus-equivalent, Type 2 matches the EVM but tweaks state internals, and Types 3 and 4 trade some equivalence for faster, cheaper proving. Higher-fidelity designs are the harder engineering problem but avoid subtle contract incompatibilities.