Its great to finally see the Alert functionality.
Few suggestion for improvement,
1. Many of us will be having other tabs open, If we are in some other tab and the alert is triggers I don't get to know as the notification just comes on the fyers web tab. It will be very useful to get sound and mobile notification also so then I can check fyers web tab.
Option to choice between few sound will also help.
If these notification can be integrated with windows notification like what we have in tradingview that will solve many other issue. As we can customize windows to do many other things.