Joachim Breitner

Serverless WebRTC instead of websocket

Published 2022-12-23 in sections English, Digital World.

For over two decades I have maintained a personal dedicated server, and hosted a fair number of websites, such as my homepage, various projects, sites of friends and family, and during its heyday even servers for DNS, email, mailing lists, Jabber, cloud storage…

But it turns out just because interests shift a bit, such running services don’t simply disappear, but keep running, just less well maintained, and then become a burdensome responsibility. So over the last year I have been moving them, one by one, off my server and elsewhere™.

Most websites are static and can easily be hosted on something convenient like Github Pages or netlify. Some are “mostly static” and require a bit more work (I might blog about that some other time), but still doable. But I had one website that I thought will be hard to host elsewhere:

A finished game of Sum Serum

On you can play a small abstract two-player game. It’s implementing the mechanics of “Sim Serim” by Heinrich Glumpler, and I built it out of a whim 9 years ago, after gifting it away and then wanting to play it. I later did get my own copy of the game, when the author discovered the online version and sent me the real thing.

You can play Sum Serum locally, then it is simply a static webpage with a bit of JavaScript code. But you can also play it with a friend remotely. It connects via WebSockets to a small NodeJS service, which makes the connection and relays messages. It works nicely, but “running a WebSocket service” is usually not part of these simple static-website-from-git services, so this was getting into the way of (eventually) decomissioning my server.

But web technology has advanced, and WebRTC, which allows browsers to talk to each other, has become widely available. So indeed, I found the trystero JS libray which provides a very simple API to connect with someone else over the internet, and using instead of my little WebSocket service was a relatively small change. Now the Sum Serum code is a purely static webpage that I can very easily host on netlify! Neat!

Granted, there are still servers involved to make the connection, as the library is using the BitTorrent network to find the peers. But as far as I am concered, that is nothing I need to worry about. Furthermore, trystero is quite easy to use, so maybe I can create more simply fun multi-use interactive thingies, now that I know I don’t have to worry about hosting a backend.


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