# Haskell Cardano is written in Haskell, a functional language that emphasizes 'pure' functions. That is, functions that produce the same result for the same input. Haskell is particularly well suited to Cardano's high-assurance code, and the need for greater formal verification in the blockchain. Cardano aims to become a global social and financial system, which requires a very high degree of reliability and verification. Many other companies use Haskell, both because of its security properties and pure functional nature. Well-known firms like Oracle and Facebook use Haskell for blockchain research and advertising, respectively, while lesser known companies such as Atos IT and Jotron use it for building applications for the aerospace industry. [Why Cardano Choose Haskell and why you should care](https://medium.com/@cardano.foundation/why-cardano-chose-haskell-and-why-you-should-care-why-cardano-chose-haskell-and-why-you-should-f97052db2951) --- # 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://cardano-wiki.gitbook.io/cardano/developer-portal/developer-portal-contents/programming-languages/haskell.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.