Purportedly Browserstack can be used to do "local testing". When using Chrome or FireFox this default supported and should work transparently.
There is not a lof of documentation on how this should work so this makes me wonder if this is done in practice.
For example, I have a private website that I can only reach using the proxy server that is also used to access public URL's. I think that Browserstack considers this website public somehow and so it fails to reach this website.
Also I noticed - since installing the Browserstack extension - FireFox is crashing like there is no tomorrow.
This also makes me wonder how well this works in practice. I can't imagine any serious testing being done with combination of FireFox/Browserstack and local testing.
Is Browserstack used in practice for testing private servers? How is this done?
Currently browserstack doesn't support local testing via extension when your local testing server is behind a proxy.
In this case you need to use Browserstack binary with parameters
./BrowserStackLocal --key <your_key> --proxy-host <proxy_host> --proxy-port <proxy_port>
Binary can be used to do Live testing on safari/IE or to run automate tests.
If you are facing issues while using your extension (i.e. firefox crashing) . I would recommend you to contact support @browserstack.