Haskell

An LD47 submission: https://ldjam.com/events/ludum-dare/47/orboros

Oats takes an API description in a subset of OpenAPI format and generates schemas, types and endpoint methods or functions. It relies on io-ts library for runtime validation, sparing front-end developers from tedious debugging caused for example by a bug on a back-end or a mismatching API version.

Video chat written in Haskell and Javascript.

Imageboard engine written in Haskell and powered by Yesod

Add a declarative gtk user interface to a set of command line programs

Haskell discord bot

CGAL Haskell Bindings

PDP11 on Servant / server

Fagario is a agar.io clone written with functional languages.