I am sorry if this has been discussed before, but I could not find any posts related to this and the developer docs do not explain this either.
Instead of creating a theme by customizing the stock ember js app, i would like to create my own front end app (using next js).
I wonder if this is something that would be reasonable enough to do, or if this would require some hacky code.
If it is possible, is there any documentation for this? I really could not find anything.
Thank you,
Lukas
I am familiar to quite a few tries of using Discourse as only an API and rewriting the whole front-end and it always end up badly, as people subestimate the sheer size of our front-end app. Also there is no versioned API, so while you can target our latest stable version and build your app in a few months, you will have go back every six months and fix all the compatibilities with the newly launched version.
The most common API endpoints are documented at https://docs.discourse.org/.
As a designer here at Discourse, I would say that creating an entirely new front end would not be reasonable or worth the effort. EmberJS while different, is very much like most front end frameworks in the way it works.
The emberJS community is also pretty helpful and vibrant as well. Id suggest using the time you would have devoted to building a new front end with NextJS to learn EmberJS 
After that, you’ll have a knowledge of two frameworks AND the ability to create custom themes & theme components for Discourse forums.
If that works for you, I’d start by taking a look at this popular & helpful topic.