Does next.js need its own server?

[bexoss]

The app based on create-react-app, I can build client code and without its server, I can run this app with just one express server (express will serve /build/.html).

In next.js, I read some official documents, It's seem to I should run next.js server. (npm run build => npm run start).

So, should I run at least 2 node.js instance for running next.js based app?

[Timer]

You should host them separately, yes.

However, take a look at Next.js' API routes feature:
https://nextjs.org/docs/api-routes/introduction