The battle against spam and malware on Facebook is aided by the unique Sigma system, designed to automatically identify and remove malicious content. Recently upgraded to Haskell, Sigma serves over one million requests per second, a rare choice for such large production systems. Haskell’s functional programming and strong typing capabilities enhance safety and efficiency, allowing for quick policy deployment and improved performance. The Haxl framework automates data-fetching operations, while GHC’s Applicative do-notation facilitates code updates seamlessly. Despite initial challenges, Haskell has proven to be a reliable and high-performing tool in Facebook’s fight against abuse, with potential for future enhancements.
https://engineering.fb.com/2015/06/26/security/fighting-spam-with-haskell/