What have they been engineering over there? You would think after this amount of time twitter could just keep running with hardly any human intervention.

If nothing else, security updates across their fleet of machines is incredibly non-trivial.

Do they still use React Native Web? Our product went off a cliff when it got introduced and every component had to be refactored to be identical on both web and native mobile. Twitter using it was one of the selling points that allowed it to slip in. My memories of it are not fond.

For Twitter the backend infrastructure is what's interesting, half of which is dedicated to storing data.

If Twitter were to break, where (aside from HN) would we post about Twitter being down?

It's probably something like 50/50 if it gets talked about to death on Mastodon or entirely ignored/unnoticed, depending on your instance and follows. May just be a stream of mocking memes.

Engineer's & anonymous programmers at Twitter discuss how Elon Musk's layoffs are slowly causing the ancient and unattended code base to slowly fall apart.