A zero-knowledge rollup is a Layer 2 blockchain solution that performs computations and storage off-chain while funds are held in a smart contract. The solution came in the form of Layer 2 blockchains and additional developments like zero-knowledge rollups. Hermez implements these solutions and Polygon acquired them. HermezJS is an open-source SDK to interact with Hermez Rollup network. It can be downloaded as an npm package, or via github. In this tutorial we will walk through the process of using the SDK to use Zero Knowledge Rollups for simple transaction use cases.