Setting Up NextJS 13 with Auth0 and Sub-Domains: A Guide to Multi-Tenancy Web Apps

Hi guys! In the article today we'll discuss and also I'll show you how to set up NextJS 13 (with app folder), Auth0 and sub-domains. I'm currently working on a web multi-tenancy app. So we need multiple sub-domains. For security reasons, we decided to use Auth0. We did follow the basic setup for Auth0 which can be found here . And everything worked smoothly and fine. But, we figured out that, we need the multiple sub-domains. So, I started researching, I got into a lot of trouble with this because every time I entered subdomain.domain.com I got an error. Something about err callback, grant_type etc, I can't reproduce the error now, but the status code was 400. Anyway, after a lot of research, a colleague of mine, has found that we need to create our sdk. If you followed the basic quickstart from Auth0 you should have something like // src/api/auth/[auth0]/route.ts export const GET = ( req : NextRequest , res : NextResponse ) => { return handleAuth ()( req , res ); // not neccesary to h