When comparing Hapi vs Phoenix, the Slant community recommends Phoenix for most people. In the question“What are the best backend web frameworks?” Phoenix is ranked 1st while Hapi is ranked 27th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Backed by a major corporation
Hapi was developed and is still being used by Walmart. Being backed by such a major company means that it will not lose support any time soon and most importantly it's being developed by professionals and that you will always get support for it.
Pro Consistency across applications
Hapi's philosophy is that configuration is more important than code. This is especially useful for very large teams because it helps developers maintain consistency and reusability throughout their code.
Pro Very positive reviews
Pro Relatively big community
It has the biggest community from all Elixir web frameworks so there are examples and tutorials all over the place and you can quickly find help.
Pro Easy to learn
The official guides are really well written.
Pro Will be easy to learn for Rails developers
Cons
Con Requires too much boilerplate
Hapi seems to be made with large applications in mind. The sheer amount of boilerplate code it requires is simply not practical for a small web app. This also means that there are few examples of Hapi applications around for beginners to learn from.