Airbnb, Kickstarter, Twitch, GoodReads, Bloomberg, there is quite a list of companies who still run a significant amount of their site through Rails. Over time I imagine that particular bottlenecks and performance critical pieces have been pulled out into other languages and services as necessary, but I certainly wouldn't feel bad about it if I was developing or maintaing a Rails site today. It's significantly better than PHP, and a hell of a lot of sites are still run on that. The reality is that if you really need to scale, your primary bottleneck will probably be the datastore, not the frontend.

GitLab rewrote some parts in Go, because Ruby was too slow on a big scale.

So “use rails until you raise a C round?” heh

I'd say it's more use Rails for all of your standard CRUD operations and then use Go as a module in Rails using Quartz/FFI if you have any algorithms that need to be high performance. Of course you could always go down the microservice route and spin up a Python/Go service for your more intensive data processing modules.

Exactly, we use Rails for most of the functionality and Go for the functionality that gets used most.

Start with Rails and optimize in Go for the services that get expensive to run in Rails, like https://gitlab.com/gitlab-org/gitaly

I don't have any serious comment, but love "gitaly" as a project name.

if that was a pun on the C language, then I officially groan

Twitter is more of a counterexample I think

Twitter using Rails to grow to the point where Rails became the problem was actually Rails's selling point. If you ever grow to the point where Rails is your problem, then you have money to solve that problem. But if Twitter hasn't used Rails, they might not event get to the point where their product is out the door.

It's absolutely correct to say Twitter blamed their issues on Rails. It's less likely to be correct that they wouldn't need a similar major change if they had started with anything else and grew from an MVP to one of the busiest sites in the world. I personally find it doubtful that they couldn't have done it with Rails.

Stripe too