Redirect UI page from nodejs for OAuth

I am working with Pocket API to get the access token. I have obtained the request token using a POST request.

Now i have to redirect the UI page to show:

http://ift.tt/1yGSsGI

I tried:

res.writeHead(301, {Location: redirectUrl} );
res.end();

And

res.redirect(redirectUrl)

But they make a POST request without redirecting the UI page to authentication page.

How can i get the access token in this case.