A comparison between Ur/Web and some other functional programming frameworks.
|Framework||Documentation||Commercial support||License||Programming language(s)||Server-side execution model||Free of garbage collection overhead|
|OPA||Outdated||Yes||AGPL or Commercial||OPA||Native code||?|
|Play with Scala module||Yes||Yes||Apache 2||Scala||JVM||No|
|Lift||Incomplete / outdated||Yes||Apache 2|
|Play with Scala module||Yes||No||Yes|
It is not really worth trying to measure "maturity" here, as none of the frameworks on this page have seen huge takeup thus far, and in any case it should be remembered that a "mature" web framework is not necessarily a modern or well-designed one.
There is also no point in comparing free support, since any web framework these days, unless it is a totally dead project, will have free support from the community.
Stateless means that no state is no retained in the application server (as opposed to the database, or the web browser) between requests.