NGINX - Send request to backend if the request is coming from a crawler/bot
Solution 1:
The hash # and contents after it are not sent to the HTTP server, so they are not a part of $request_uri variable.
With your example configuration, what is the exact request your backend receives?
I don't have experience with single page apps and Google, but I don't think it is a good approach to send different content to crawler bots than to end users.