felix-arntz.me

Hi I’m Felix!

I build software and developer tools on the web. Born in Germany, I later relocated to Zurich and then to San Francisco, where I’m currently living.

I work as a Senior Software Engineer at Google, where I am working on AI evals for web app code generation and coding assistance quality.

I am also a WordPress Core committer, and a co-founder of the WordPress AI Team and the WordPress Performance Team. I created and maintain the PHP AI Client SDK and its WordPress-specific wrapper.

I have both contributed to and led engineering of various open-source projects which are used by millions of people around the globe.

Felix Arntz (2025)

Projects I have contributed to

WordPress Core
Performance Lab plugins for WordPress
Site Kit by Google plugin for WordPress
PHP AI Client SDK
Yoast SEO plugin for WordPress
HTTP Archive custom metrics project
Gutenberg feature plugin
AMP plugin for WordPress

WordPress Core contributions

I have been a WordPress Core Contributor since version 4.3 which was released in August 2015. I’m currently a component maintainer of the Multisite component and the REST API component, but regularly work in other areas as well. With WordPress version 4.6 I was recognized as a noteworthy contributor for the first time, and since November 2016 I have been a Core Committer.

More recently, I was the first Performance Lead as part of the WordPress 6.2 release squad, the Co-Performance Lead for the WordPress 6.3 release, and later the Performance Lead for the WordPress 6.8 release. I’m currently mostly involved in the new WordPress AI Team, of which I am a founding member and initial co-Team Rep.

Over the course of time I have worked on tons of tickets and made 301 commits. Working on WordPress Core and other open-source projects is a high priority for me, so I ensure I have sponsored or personal time available to dedicate to it.