# Starknet Starknet is a permissionless, Validity-Rollup, also known as a zero-knowledge rollup (ZK rollup) for Ethereum. It operates as a Layer 2 (L2) blockchain, enabling any dApp to achieve massive scale for its computation without compromising on Ethereum’s composability and security. Starknet aims to achieves secure low cost transactions and high performance by using the STARK cryptographic proof system. Starknet contracts and the Starknet OS are written in [Cairo](https://github.com/starkware-libs/cairo), a custom-built and specialized programming language. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://doc.data123.io/reference/api-reference/starknet.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.