Our favorite GitHub repos

The trendy five: Ring in the new year with the coolest GitHub repos of December 2019

Sarah Schlothauer
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It’s that time of month again, time to browse the GitHub trending page and pick the best, coolest, or most impressive open source projects for the month. December 2019 was full of great repos, and as always, it’s hard to narrow it down to just the top five. Last month we saw a way to make Docker containers smaller, a helpful source code explorer, and more.

Every month, we go over the GitHub trending page for any cool repos that stand out from the crowd. We choose five of the most innovative, interesting, and well-thought-out projects to highlight in our monthly report. As always, it was tough to narrow down the list of GitHub repos to our five favorites.

So, in no particular order, here are our top picks for December 2019.



Sourcetrail user interface sample. Source.

This helpful tool became open source software and has been trending on GitHub since then. Sourcetrail is an interactive source code explorer that helps developers learn and understand what is going on in existing source code, providing useful context.

The UI consists of three different parts: search, graph, and code display.

Since Sourcetrail does not establish an internet connection, all confidential code is secure. All data remains securely on your local machine.

Test it out: Sourcetrail supports several code editors including Atom, CLion, Eclipse, Emacs, IntelliJ IDEA, Vim, and Visual Studio Code.


Optimize your containers with docker-slim , without having to do the heavy lifting yourself. DockerSlim can minify your containers, making them up to 30x smaller; no need to optimize your containers by hand. Notably, DockerSlim doesn’t require any new tools or changes to your workflow. As a bonus, it also makes your containers more secure.

It is ready for use in production and works in any Dockerized app.

From the README:

docker-slim will optimize and secure your containers by understanding your application and what it needs using various analysis techniques. It will throw away what you don’t need, reducing the attack surface of your container. What if you need some of those extra things to debug your container? You can use dedicated debugging side-car containers for that (more details below).

View the minification examples on GitHub and see how slim it can go. So far, DockerSlim has been used with Node.js, Python, Ruby, Java, Go, Rust, Elixir, and PHP and has been run on Ubuntu, Debian, CentOS, and Alpine Linux.

Geo Heatmap


Map sample. Source.

Geo Heatmap is a script that generates your own interactive heatmap using data from your Google location history with Python 3, Folium, and OpenStreetMap under the hood. Track your footsteps and see where you spend your time, or just marvel at the creation.

You will need to do is download your location data from Google, which is provided as a JSON file by default.

(Never downloaded your data from Google from before? Now is a good time double-check and see what data Google is storing about you.)


Detect fraud and identify users with accuracy using Fingerprint.js, a flexible fingerprinting library. Since this library is written in pure JavaScript, the API is easy to use anywhere. No frills, no extra dependencies, and no cookies necessary. It even works with low-powered mobile devices.

Let’s see how Fingerprint.js works. According to the website:

Fingerprint.js employs the most advanced methods of identification available: canvas fingerprinting, audio sampling, WebGL fingerprinting, font detection and browser plugin probing. Every method will help you catch more bad actors on your website.

Configure the options and only choose the components that you need in the fingerprint. Or, leave the default settings. The choice is yours.


This open source email app for Android focuses on privacy and works with most email providers, including big names such as Gmail and Outlook. FairEmail lets you take control of your privacy instead of relying on closed-source apps.

FairEmail is minimalistic, small (roughly 12 MB), and doesn’t drain your battery or use up all your mobile data. It is fully open source, can host unlimited email addresses, unlimited accounts, and offers offline storage and operations. Set up is quick and its design is simple, concentrating its efforts on just the basics: reading, writing, and sending emails.

For additional privacy, FairEmail supports encryption with OpenPGP and S/MIME. Better yet, it does not track you, there are no ads, no analytics, no special permissions, and even error reporting is opt-in.

That’s all for this month! See you in February with the next batch.


Sarah Schlothauer

Sarah Schlothauer

All Posts by Sarah Schlothauer

Sarah Schlothauer is the editor for She received her Bachelor's degree from Monmouth University, West Long Branch, New Jersey. She currently lives in Frankfurt, Germany with her husband and cat where she enjoys reading, writing, and medieval reenactment. She is also the editor for Conditio Humana, an online magazine about ethics, AI, and technology.

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