Julien Bet His Career on Replacing PHP at Facebook | The Hack Story

Julien Verlaguet didn't just write code at Facebook — he tried to change the language 4 billion people's apps were built on.In this episode of Computers, Coffee, & Beer, Julien tells Keith Adams the full inside story of creating Hack: a gradually typed dialect of PHP that brought static analysis, type safety, and sub-50ms error feedback to one of the largest codebases on Earth.It started as a security project. It became an "adventure" — one that involved pitched battles with the HHVM team, developers who associated type systems with traumatic C++ compile times, and the realization that Facebook's "spaghetti noodle" dependency graph made strict typing nearly impossible.If you've ever wondered what it takes to introduce a new programming paradigm inside a company running at Facebook's scale — the politics, the engineering, the human friction — this is that story.🔗 Follow Computers, Coffee, & Beer for more war stories from the engineers who built the modern internet.Chapters:0:00 - Intro: Meet Julien Verlaguet2:15 - Why Hack existed: PHP's security problem7:17 - The pitch to the HHVM team (Keith's "okay kiddo" moment)15:30 - Gradual vs. optional typing explained28:00 - Facebook's spaghetti dependency graph problem45:00 - Building a sub-50ms type checker1:09:09 - The nullable salt vulnerability (why weak typing is dangerous)1:15:26 - "TypeScript for PHP" — Hack's legacy1:51:46 - The C++ developer's scar: winning over type system skeptics1:54:53 - The George Lucas / Steven Spielberg analogy for innovation🎧 Full episodes on YouTube + your favorite podcast app. @ComputersCoffeeandBeer  📩 For Business Inquiries: [email protected] =============================Channel About: Computers, Coffee, & Beer is hosted by Keith Adams and Julien Verlaguet — two engineers who helped shape the modern internet and have the war stories to prove it. Keith built the HHVM JIT compiler at Facebook, helped virtualize the world at VMware (employee ~80), and went on to Slack before founding Pebblebed, an early-stage VC firm for technically ambitious founders. Julien created the Hack programming language, spent years writing safety-critical compiler software for Airbus and nuclear plants, and now runs Skip Labs. Together they dig into the systems, languages, and decisions behind the technology that actually runs the world — told by two people who were in the room when it happened.=============================#Hack #PHP #Facebook #Programming #TypeSystems #HHVM #SoftwareEngineering #DevTools #ComputersCoffeeBeer