The ABS playground: run ABS code directly in your browser (WHOOOOP!)

Remember the last time you thought “ough, JavaScript”?

Well, that’s me every other day: I love JS for its flexibility and dynamism, but I also sometimes find it painful to deal with, especially in some specific programming contexts.

If you, like me, hoped to be able to write something other than JavaScript in order to get stuff done on the web, chances are you bumbed into WebAssembly (abbr. WASM), and considered it your holy grail. WASM is a portable binary format that’s been implemented by all major browsers and allows other languages to be compiled for the web.

Why is that important? Well, that’s the key of how I managed to run an ABS playground (a code runner) on the browser.

The original issue

One of ABS’ main contributors, Ming, smartly suggested that it would be interesting to let users play around with ABS without having it installed on their systems.

My first thought was to replicate the Go playground, but that would have meant setting up a server-side code-runner, and that would have required more time (maintenance) and money (server cost) that we had on hand.

We abandoned the idea of a code runner for a while, until we thought of something creative…

WASM to the rescue

Go recently added support for WASM as one of its compilation targets, meaning you can run Go applications on the browser — you just need a simple GOOS=js GOARCH=wasm go build -o script.js script.go and you’re set with an executable that can run within the browser.

I then thought: what if we could compile the ABS interpreter, which is purely written in Go, to WASM?

The result is a simple “JS” distribution of the ABS interpreter, 50 lines of code that bring ABS to the browser!

The downside of compiling Go into WASM is that the binaries are a bit heavy (ABS is 4.3 MB), but, considering that this is more of a proof-of-concept than a serious attempt to run ABS in the browser, I can’t really complain.

Armed with a distribution of the ABS interpreter that can run within your browser, I then setup a silly HTML page in our docs that would load the WASM binary and give you a textboxt to play around, which brings me to the big announcement…

Welcome to the ABS playground!

Without further ado, please head over to

You can try most of ABS’ features directly in the web editor: simply write some code, hit Ctrl+Enter and see the result pop in front of your eyes!

Let me know if you have any feedback!

In the mood for some more reading?

...or check the archives.