# Home

## Hi I'm Felix!

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

I work as a Senior Software Engineer at Vercel, where I am part of the AI SDK team.

Previously, I was at Google for over 7 years, working web performance optimization for CMSs, launching the Site Kit product, and AI evals for web app coding assistance.

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)](https://felix-arntz.me/wp-content/uploads/2025/12/felix-arntz-profile-2025-1024x1024.webp)

## Projects I have contributed to

[![AI SDK](https://felix-arntz.me/wp-content/uploads/2026/02/ai-sdk-logo.webp)](https://github.com/vercel/ai)[![WordPress Core](https://felix-arntz.me/wp-content/uploads/2025/01/wp-logo-png.avif)](https://github.com/WordPress/wordpress-develop)[![PHP AI Client SDK](https://felix-arntz.me/wp-content/uploads/2025/12/wordpress-ai-logo.webp)](https://github.com/WordPress/php-ai-client)[![Performance Lab plugins for WordPress](https://felix-arntz.me/wp-content/uploads/2025/01/performance-lab-icon-png.avif)](https://github.com/WordPress/performance)[![Site Kit by Google plugin for WordPress](https://felix-arntz.me/wp-content/uploads/2025/01/google-site-kit-icon-png.avif)](https://github.com/google/site-kit-wp)[![Gutenberg feature plugin](https://felix-arntz.me/wp-content/uploads/2025/01/gutenberg-icon.avif)](https://github.com/WordPress/gutenberg)[![Yoast SEO plugin for WordPress](https://felix-arntz.me/wp-content/uploads/2025/01/yoast-seo-icon.png)](https://github.com/Yoast/wordpress-seo)[![HTTP Archive custom metrics project](https://felix-arntz.me/wp-content/uploads/2025/01/httparchive-logo.png)](https://github.com/httparchive/custom-metrics)

## Latest posts

## 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 ](https://make.wordpress.org/core/components/networks-sites/)and the [REST API component](https://make.wordpress.org/core/components/rest-api/), 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](https://make.wordpress.org/ai/), 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 \[wp\_core\_commits\]. 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.