StarkNet is a permissionless decentralized Validity-Rollup (also known as a “ZK-Rollup”). It operates as an L2 network over Ethereum, enabling any dApp to achieve unlimited scale for its computation – without compromising Ethereum’s composability and security, thanks to StarkNet’s reliance on the safest and most scalable cryptographic proof system – STARK.
StarkNet Contracts and the StarkNet OS are written in Cairo – supporting the deployment and scaling of any use case, whatever the business logic.
A variety of teams and individuals are taking part in building StarkNet and its developer tools.
You can see the list of projects building on StarkNet here.