How can browser and mobile app testing be so difficult?

Share Episode We welcome David Burns, Head of Open Source at BrowserStack and previously Mozilla, this week to help explain how can browser and mobile app testing be so bad still in 2026. "Even if we had to do it all over again, we probably still wouldn't have gotten it right", might just be the biggest learning. We review some of the core challenges that cause even the most experienced web engineers pain and how some companies are attempting to avoid them. We also review shares lessons from Mozilla’s 'War on Orange,' demonstrating why chasing a 100% green CI suite at scale is a fool's errand, and why engineering teams must instead manage delta tolerances and adhere to a strict testing pyramid. Additionally, we investigate the physical hardware nightmares of running 30,000 real phones in data centers; from battery swelling and custom Faraday cages to complying with Apple EULA requirements using racks of Mac Minis. And finally, we discuss WebMCP, Project Fugu, and why LLM browser agents still struggle against edge-case browser behaviors like the Back-Forward Cache (BF Cache). 💡 Notable Links: ✨ Episode: Sam Goto — Security challenges in the Browser World ✨ Episode: Actually think about how are your users use your tools Mozilla CI - Tree Herder The Worst UX site with a perfect 100 Project Fugu Browser initiative WebMCP Project Specification 🎯 Picks: Warren - Paper — The Corporate Bullshit Receptivity Scale David - Anbernic Retro Handheld Game Console