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The ReaderT Design Pattern (2017)

Michael Snoyman describes the ReaderT pattern for structuring Haskell applications, recommending a core Env data type holding runtime configuration and global functions, with application logic living in ReaderT Env IO. He notes this underpins Yesod's Handler type and much of the Stack codebase, though acknowledges it remains opinionated and not universally adopted.

Background

Michael Snoyman is a prominent Haskell developer known for creating Yesod and maintaining key Haskell tooling like Stack and aeson. This article presents his personal best practices for application architecture in Haskell.

Source
Lobsters
Published
Aug 26, 2026 at 08:20 PM
Score
5.0 / 10