Unfortunately Klarna is consolidating tech stacks on Java/Javascript. Erlang/Scala/Haskell/Clojure (ordered) will probably stay for a couple of more years, but these will over-time be replaced by new systems in Java and Javascript. The main reason is ease of hiring, but also to be able to move engineers and systems around easily within the organisation.
I worked there a few years ago. I applied for a Haskell role there. During my interview I was told it was a Scala role.
I became the only Scala dev in a team who wanted to rewrite the codebase in Typescript.
I ran out of work to do there at times - while the team was still growing. The same manager who couldn't find work for me, after announcing that the team would be splitting because it got too big, was dumbfounded when I suggested we stop hiring more people.
I had a few colleagues who had worked there longer than me, but didn't have any code in prod.
I feel stupid even writing this, but it honestly seemed that having more developers was more important than the product itself.
When VCs give you money you're required to spend it.
Otherwise what the hell did you go out and raise more money for? More engineers is the easiest way to spin wheels and make money go away without a lot of questions being asked.
It's one of the sad realities and cargo cults that we all participate in.
Getting hired to a Haskell or Elixir/Erlang role in a bootstrapped company is the dream but there's only so many of those jobs out there right now, sadly.
I honestly believe that removing Typescript/JS would actually benefit the software engineering quality in the company, to me it's there just because the pool of people is large. I would prefer quality over quantity, but I'm not a manager ¯\_(ツ)_/¯
