9 Tools Big Tech Uses Internally (Now Open Source)

Most "best tools" lists are just GitHub trending with extra steps. Same 10 repos. Same README marketing. Nothing that shows you how teams shipping at scale actually build their internal systems. The actually interesting tools got built by engineers who had no choice but to build them. Spotify needed to navigate 2,000 microservices. Uber needed workflows that didn't die silently. YouTube needed MySQL to scale horizontally. None of them built these tools for GitHub stars — they built them to survi