About

I'm Julien Danjou. I've spent the past 25 years building open-source software, writing about it, and occasionally convincing other people to do the same.

The early years

I became the youngest Debian developer in 2002. From there I worked on GNU Emacs, got deep into Lisp, and created the awesome window manager — if you've used Linux, you might have heard of it.

Python and cloud

I discovered Python in 2007 and never looked back. In 2011 I joined the OpenStack project, where I led the telemetry projects and built Gnocchi, a time series database. I continued that work at Red Hat starting in 2014, pushing the boundaries of cloud-scale telemetry.

Books

I wrote and self-published two books: Serious Python (2014, revised 2019) and Scaling Python (2017). Together they've sold over 25,000 copies.

Datadog

In 2019 I joined Datadog to build a Python profiler from scratch — an excuse to spend a lot of time inside CPython internals.

Mergify

Since 2019 I've been CEO and co-founder of Mergify, a SaaS platform that helps engineering teams merge code, manage CI/CD, and ship faster. Talking to our users taught me a lot about CI/CD, which led me to launch Nom d'un Pipeline !, the first French podcast on the topic, in 2023.

Today

Based in Toulouse since 2021 (after many years in Paris), I run the Toulouse SaaS Club, a non-profit for local SaaS founders. I advise startups and speak at tech conferences.

When I'm not coding, I'm perfecting my Neapolitan pizza recipe, smoking meat on my kamado, training for half-marathons, or climbing FPS leaderboards — Master in Apex Legends, Global Elite in CS:GO.