How does the middleware file look like? You could be returning prematurely from the function, or your log call could be unreachable.

I make the call in the top of middleware function. I have two functions and a config object in the file

function getLocale(req: NextRequest): string | undefined {
  ...
  return locale
}

export function middleware(req: NextRequest) {
  const pathname = req.nextUrl.pathname
  console.log("pathname: " + pathname)
  ...
}

export const config = {
  matcher: ['/((?!api|_next/static|_next/image|res|favicon.ico).*)']
}

Maybe I don't understand how middleware works.

is it in your root dir

It has to be placed at the root of your project in order to be executed

I know. It is in my root folder

Have you tried killing the server and restarting it?

Yes. I also tried to navigate to the routes using lang parameter. (like localhost:3000/en)

Clearly the middleware call is skipped for some reason. Are you sure you have the file in ./ and not ./src?

Yep:

@Dayo Why though? In documentation it says

Use the file middleware.ts (or .js) in the root of your project to define Middleware. For example, at the same level as pages or app, or inside src if applicable.

Oh wait, while it says root, it also says at the same level as app...

@Dayo @not-milo.tsx Moving middleware into /src/ solved the issue! TY all

Great