A blog on software engineering by Trevor Brown

Erlang Cheatsheet

Erlang cheatsheet webpage screenshot

I have been writing Erlang for over 4 years now and there are still a few things I struggle to remember. Remembering all the core concepts is easy but it can be hard to remember the nuances of exit signals or exit trapping. Through the years I have cobbled together some notes on the things I found hard to remember, and I finally compiled them all into a presentable format. I created a printable cheatsheet from my notes that documents the easily forgotten quirks of the language. This cheatsheet isn’t intended for beginners because it does not cover any of the fundamentals of the language.

The cheatsheet is available for you to freely print or download at The source code has been released under the MIT license and is available on GitHub at Stratus3D/erlang-cheatsheet.

I’d really like to hear your thoughts on the cheatsheet. Is there something my cheatsheet is missing? Is there something that can be simplified or removed? What do you think of the design?

Let me know via email or twitter. If you want to contribute directly feel free to create an issue or pull request on the GitHub repository.



Why Erlang?


With web applications today there is an increasing need for systems that can scale up easily and tolerate the network, hardware, and software errors that occur at scale. Building such systems is challenging, if not impossible, to do in many popular programming languages today. Erlang was designed for telephone systems where uptime requirements were law, and as such was designed to solve these challenges. In this talk Trevor will show how Erlang can be used to solve some of the most challenging problems software developers face today. He will introduce concurrency constructs that Erlang provides and show how they can be used to build reliable and scalable applications. This talk will focus mostly on the new concepts introduced by Erlang, but Trevor will also do a few demos and show code samples to illustrate some of the concepts.


Let's Encrypt on WebFaction

I have finally gotten around to installing Let’s Encrypt SSL certificates on all the websites I run. I use WebFaction (affiliate link) for my web hosting and that meant I had use their API for installing certificates. Rather than just placing the certificate files directly on the server I had to use their XML-RPC API to install the certificate. I quickly discovered the letsencrypt-webfaction gem which makes the process of obtaining and installing certificates on WebFaction easy. In this blog post I’ll explain what I did to get everything installed and configured.