Haskell is most comfortably written from the command centre of your own editor on your own machine, probably with the Haskell Language Server assisting your work. However, this luxury is lost if you are, say, at a conference without your workstation and want to try out a quick doodle; similarly, beginners who are evaluating whether to learn Haskell would rather prefer not having to delve into the topic of Installing Haskell before writing “Hello World”.

Other programming language communities (e.g. Rust, Ocaml, TypeScript, Go, Scala, …) have solved this with a playground: a web page that allows you to edit and run a snippet of code without installing anything. While websites exist that allow compiling and running Haskell code from your web browser, their backends are not written in Haskell (which is, of course, essential for the self-respecting HIW attendee), nor do they have Haskell-specific features such as giving a Core printout.

We present a work-in-progress Haskell playground, written in Haskell: https://play-haskell.tomsmeding.com/ (with contributions by Julian Ospald). The backend is horizontally scalable (distributable over multiple compute servers). Even early in its development, the playground already found use as a pastebin for runnable snippets of code in the #haskell IRC channel.

In the talk I will demo the tool, present some of the architectural choices and possibilities, and share (and poll!) ideas for further development.