Talk: (English)

Comparing two type-level Haskell web service frameworks

Web developers write a lot of code that is not very interesting, and still allows for making mistakes, like serialization functions, swagger docs, API client handlers, mock services for testing, and more.

We give an overview of two Haskell libraries that allow the user to write less code and exclude more errors at compile time: mu and servant. Servant has been around for years and is widely used in production for implementing traditional rest APIs, but also for serving HTML pages and really anything HTTP; mu is quite new and was introduced for writing gRPC services, but as a framework both are potentially solutions for the same set of problems.

In this talk, we will show code examples on how the Haskell type system supports the developer in building services, and try to give a sense which library you want to look into next for your own projects.

Arian van Putten


Arian van Putten is a passionate developer with a strong theoretical background in type Haskell theory, functional programming and compilers, but also a love for DevOps and Linux. He has studied at Utrecht University and is now working for as a backend engineer.

Matthias Fischmann

17 years ago, while completing his diploma at the Max Planck institute for Computer Science, Matthias Fischmann implemented his thesis in Haskell and has never looked back from functional programming since. His more recent projects in Haskell include an interactive platform for schools and a platform for identity management. He received his doctorate from Berlin’s Humboldt-Universität. These days, he works for Wire as a software architect.