How to "combine" API server and application in nginx?

Question

Nginx

There is an application in the form of static files. I distribute them to nginx.
The application uses the API server and accesses it using links of the type '/api/blah'. for Dev, a webpack server is configured that proxies the API. In general, the API runs on a different port.
How to combine this in nginx config i.e. distribute static and proxy API at the same time? To make the application think that they are in the same place.