[ksec]

Performance, scalability or ultimately cost. Remember 10 - 15 years ago when Twitter was using Ruby it was a lot slower. Even without YJIT CRuby today would still be 2 - 3x faster than then. Tooling wasn't as good, Hardware were a lot more expensive at the time. So when you have news spread out about how RoR cant scale cheaply, they jump to newer and shinier things like Node.

I would guess running RoR today is 100x cheaper than 10 years before. And will continue to improve as we get ZJIT or running on top of JRuby.

[vidarh]

When Twitter was using Rails it was also using a totally broken architecture that was way too centralised. Their replatforming also involved rearchitecting.