I have a proxy config file which has API(web service) link to target to make calls to our database. This proxy config is working fine locally using npm start .<
The proxy config file is for the local development web server. The main reason you use it is so you can avoid cross domain requests when developing the Angular app and the api on your local machine without having to allow cross domain requests in the api.
When you release to production there is no support for the proxy config file. You will be releasing to your production web server.
If your api is hosted under the same domain then there is no need for proxying requests as they are not cross domain and if the api is on another domain you will need to allow cross domain request in the api.