Haskell in Production: Standard Chartered

In May 2023, a Hacker News discussion examined Standard Chartered's reported use of Haskell in production, centering on their internal dialect, Mu. The bank's Core Strats team maintains over 6 million lines of Mu code, a strict-by-default variant of Haskell, within their Cortex financial analytics library. Practitioners cited strict evaluation as essential for performance analysis and predictability within their existing C++-based runtime, though it prevents direct reuse of libraries dependent on lazy evaluation.

Commenters debated whether this constitutes a Haskell success story, given the significant language modification. Some noted a recurring pattern of production teams disabling or working around lazy evaluation due to performance costs, while others argued selective strictness is the norm. On hiring, several users with industry experience contested the narrative of difficulty, stating they receive abundant qualified applicants for Haskell roles, though scaling to hundreds of developers presents a different challenge.

The discussion surfaced concrete technical trade-offs: the Mu compiler was developed for strict semantics and code mobility, trading off full ecosystem compatibility for operational needs. The thread provided no new performance data but highlighted a persistent community dialogue on evaluation strategy and ecosystem fragmentation.