maybe try this
* add /[lang]/your page etc
* deploy that to some-subdomain.yourapp.com
* rewrite [lang].yourapp.com to some-subdomain.yourapp.com/[lang]

Rewrite in Middleware or next config?

could be middleware, could be next config, you choose

i myself haven't deployed a multi-tenant app before so idk about how smoothly middleware and next config work with multi tenancy

Ok thanks! I'll try

vercel has an almost identical example of this using the Vercel Domains API here : https://github.com/vercel/platforms
There is a [domain] route and a middleware that rewrites subdomain to that route

The difference is that you are using i18n subdomain instead of custom domains, but it can help to grok out it can work out

Hi @joulev
I am in the same situation with @Mountain Quail
But I exactly need domain routing not sub-path routing.
Does app router support this in any chance?

if you don't want to do rewrites* then you have to deploy separate apps in separate domains

* note that browsers do not detect rewrites. if you rewrite from A to B, users going to A will be shown the content of B as if no rewrites happen

many, if not most if not all of, multi-tenant apps work on the basis of rewrites to subpaths. if you don't like that you have to deploy separately

But we did it with page router.
We had i18n config on next.config.js and then, you know - we got locale value from useRouter of next/router.

^^ this is my help post