Http4s VS zio-http

http4s is a Typelevel project, and therefore falls into the "program in Scala as if it were Haskell" category. Many people find this off-putting, but honestly, I think with the resources listed above, this is the option at the best intersection of "mature" and "well-documented" available in Scala. The reason it's off-putting to many people is that Haskell-style pure FP isn't mainstream, so it isn't so much a matter of learning a new technology as it is a matter of learning a new paradigm, which necessarily means surfacing and unlearning things you already know, and perhaps confronting the uncomfortable feeling that things you thought were "fundamental," "have to be that way," aren't, and don't. I personally found this process liberating. But not everyone does.

If you want a mature REST API library, I recommend http4s. Be aware, though, that it’s based on purely-functional programming with Cats, cats-effect, and fs2, so if you’re not familiar with them or aren’t prepared to commit to the paradigm, the learning curve may be daunting, seem pointless, or both.

See also cats-effect and fs2. cats-effect gives you your IO Monad (and IOApp to run it with on supported platforms). fs2 is the ecosystem’s streaming library, which is much more pervasive in functional Scala than in Haskell. For example, http4s and Doobie are both based on fs2.

Most important/known: * https://http4s.org/ - an HTTP client/server * https://github.com/typelevel/fs2 - streaming * https://github.com/tpolecat/doobie - JDBC

Scala devs are too busy wondering about free monads and F[Request[F] => Response[F]]. I am very pleased by http4s, Doobie, ScalaJS, and the whole ecosystem, really: https://http4s.org

In reality, your performance issues will not be http4s, but something else. That being said, there are improvements that http4s can and is making, and I'm quite excited about the future 1.0 release, which has some important and fundamental performance improvements already, like a a 125% performance improvement on the plaintext benchmark from https://github.com/http4s/http4s/pull/6091 - and finally, yes, akka-http does have very good performance, but you can also get good performance out of http4s.

http4s for REST services.

This is a long list of misunderstandings I don’t have the patience to unpack. Instead, let me refer you to the links in my top comment in the thread, then suggest you learn at least http4s, a purely-functional web service library that’s been used in production for a decade or so now.

The most popular nowadays are - I guess - akka-http and http4s. You can also use Play if you don't want to start from scratch but prefer a framework-based approach.

There are functional frameworks: https://http4s.org/

For JNI, make sure you have `-H:+JNI` in your native image options. Be aware that Netty is a bit of a monster to include in a native image application (I just recently added it a Netty dependency and it completely broke my project and took a good day to figure out). Mine was through zio-http and I was able to piece together some working options from github issues: https://github.com/zio/zio-http/issues/20.

What's the hardware being used for your test? I get 55k RPS with a basic 200 responder with zio-http[0] (which uses Netty) on my i5-6600K, and over 20k RPS for an e2e POST endpoint that does write batching to postgres (committing the insert before responding with the db generated id). Postgres, client (vegeta[1]), and the app all on the same machine. I think that was with keep-alive, I think like 256 clients for the basic responder and 1024 for the one that writes to the db. There's a recently merged PR for zio-http that does 1M req/s on whatever machine they test on[2] so Netty can absolutely scale to high RPS.

[0] https://github.com/zio/zio-http

[1] https://github.com/tsenart/vegeta

[2] https://github.com/zio/zio-http/pull/1659

Yep! https://github.com/zio/zio-http

I was looking at HTTP frameworks for Scala. I found zio-http, https://zio.github.io/zio-http/. Has anyone tried this framework?

https://github.com/dream11/zio-http very simple and super performant, dead easy to abstract over routes to make a router

I'm starting a new project, essentially a standard web app (SPA + rest api). I'd like to stay as functional as possible. I'm debating between http4s + cats effect, http4s + zio, and zio-http (https://github.com/dream11/zio-http). I'm having a hard time figuring out which stack has the strongest (safest?) future especially with scala 3 out. Cats Effect 3 looks amazing, but so does the zio ecosystem. Thanks for any opinions/advice!