Hermez is a zk-rollup which allows for scaling payments and token transfers on top of the Ethereum public blockchain. It is designed with high-frequency tokens like ETH, DAI, Tether, and wBTC in mind.
Polygon Hermez 1.0 version was launched in March 2021. The goal of Polygon Hermez 1.0 was to scale payments and transfer ERC-20 tokens. It focussed mainly on decongesting Ethereum main chain by taking transactions off from the main chain and executing them off-chain; this resulted in an increase in the number of transactions that can be executed per second to up to 2000, which was a big improvement over Layer 1 Ethereum. See Ethereum Live TPS to keep track of Ethereum's live transactions per second.
Polygon Hermez 2.0, henceforth called Hermez 2.0, has been developed to emulate Ethereum Virtual Machine(EVM) that executes Ethereum transactions with zero-knowledge proof validations. This has been accomplished by developing an EVM based on zero-knowledge; the machine is designed to recreate all the existing EVM opcodes that can be deployed as smart contracts. Although taking on this revolutionary design approach was a hard decision to make, the objective is to minimise the users and dApps friction when using the solution. It is an approach that requires the recreation of all EVM opcodes for the transparent deployment of existing Ethereum smart contracts. For this purpose, a new set of technologies and tools are being created and engineered by the team.