In my workplace we started our performance testing initiative to monitor any interesting trends in our product such as load or CPU, memory usage. This is a new application that has not been in production yet, so I don’t have much to go on what kind of load or usage to expect by real users.
If you are looking for a tool to test your web apps before they went live, you can try the Lambda Tunnel. It will help you perform live-interactive testing, screenshot testing, and automation testing of your locally hosted website.
Alternatively, you can try the LT Browser to perform responsive testing of your app.
But if you are looking for a strategy to get it tested somehow, I would recommend launching a BETA program for early users.