[KajMagnus]

Tapir looks nice, didn't know about. Can I ask, do you use it together with Netty? How fast is it for you? (if you happen to have benchmarked it)

Have you tried Vertx with Scala? (Or Spring + Scala, or sth else?)

> The introduction of Guice

Personally I've wired everything statically at compile time, zero dependency injections. (Felt as if what I did went a tiny bit against the framework, but works fine.)

[hocuspocus]

I use Tapir with http4s as the http server isn't my bottleneck anyway and I like Cats Effect and fs2.

But SoftwareMill has done extensive benchmarking to make sure the overhead from Tapir vs calling the http backend directly was insignifiant. I believe Netty is the recommended backend if you want direct style (i.e no effect systems) on Java 21+ virtual threads even though Oracle's Helidon Níma is supported too.

[KajMagnus]

Thanks! Ok, seems direct style is what I would want, after having asked an LLM: it says it's then simpler to debug async call stacks, with Java 21+ virtual threads.

Nice to know that there are good alternatives, if time it is some day to migrate away from Play.