I'm very interested in Scala, but I have not used it yet, so with that caveat, the frameworks I am aware of that are not mentioned in HRJ's answer (Lift, Sweet, Slinky) are:
It must be noted that there is also a considerable interest in Wicket and Scala. Wicket fits Scala suprisingly well. If you want to take advantage of the very mature Wicket project and its ecosystem (extensions) plus the concise syntax and productivity advantage of Scala, this one may be for you!
There's a new web framework, called Scala Web Pages. From the site:
Target Audience
The Scala Pages web framework is likely to appeal to web programmers who come from a Java background and want to program web applications in Scala. The emphasis is on OOP rather than functional programming.
Characteristics And Features
Adheres to model-view-controller paradigm
Text-based template engine
Simple syntax: $variable and <?scp-instruction?>
Encoding/content detection, able to handle international text encodings
I tend to use JAX-RS using Jersey (you can write nice resource beans in Scala, Java or Groovy) to write RESTul web applications. Then I use Scalate for the rendering the views using one of the various template languages (JADE, Scaml, Ssp (Scala Server Pages), Mustache, etc.).
Both Sweet and Slinky seem to be unmaintanted for about a year. Sweet Maven repo sweetsoftwaredesign.com is dead so there's even no way to download dependencies.
uses the fantastic Akka library and actors to scale
uses servlet API 3.0 for asynchronous request handling
is modular (replacing components is straight forward)
uses DSLs to cut down on code where you don't want it
supports Scalate and Freemarker for templating
Spiffy is a web framework using Scala, Akka (a Scala actor implementation), and the Java Servlet 3.0 API. It makes use of the the async interface and aims to provide a massively parallel and scalable environment for web applications. Spiffy's various components are all based on the idea that they need to be independent minimalistic modules that do small amounts of work very quickly and hand off the request to the next component in the pipeline. After the last component is done processing the request it signals the servlet container by "completing" the request and sending it back to the client.
You could also try Context. It was designed to be a Java-framework but I have successfully used it with Scala also without difficulties. It is a component based framework and has similar properties as Lift or Tapestry.
I have stumbled upon your question a few weeks back, but since then also learned about Circumflex. This is a nice, minimal framework that is therefore easy to learn, and it has pretty good documentation available as well.
Beside it's minimal-ness, it also claims to work well with other libraries and lets you use your own implementation of things when you need it.
Prikrutil, I think we're on the same boat. I also come to Scala from Erlang. I like Nitrogen a lot so I decided to created a Scala web framework inspired by it.
Take a look at Xitrum. Its doc is quite extensive. From README:
Xitrum is an async and clustered Scala web framework and web server on top of Netty and Hazelcast:
It fills the gap between Scalatra and Lift: more powerful than Scalatra and easier to use than Lift. You can easily create both RESTful APIs and postbacks. Xitrum is controller-first like Scalatra, not view-first like Lift.
Annotation is used for URL routes, in the spirit of JAX-RS. You don't have to declare all routes in a single place.
Typesafe, in the spirit of Scala.
Async, in the spirit of Netty.
Sessions can be stored in cookies or clustered Hazelcast.
jQuery Validation is integrated for browser side and server side validation.
i18n using GNU gettext, which means unlike most other solutions, both singular and plural forms are supported.
Conditional GET using ETag.
Hazelcast also gives:
In-process and clustered cache, you don't need separate cache servers.
In-process and clustered Comet, you can scale Comet to multiple web servers.
It is now production ready. It incorporates: a cool template framework,automatic reloading of source files upon safe, a composable action system, akka awesomeness, etc.
Having used it for two projects, I can say that it works pretty smoothly and it should be something to consider next time you are looking to learn new web frameworks.
