Alert simulator

The alert simulator sends test alerts (a follow, a subscription, a donation, a raid) into a web overlay, so you can check how your alert box looks and sounds without waiting for a real event or going live.

It is in every app (the Linux app’s since 2026-10-26). It needs a web overlay layer in your collection.

Sending a test alert

Select a web overlay layer and open Alert Simulator in its properties (the macOS, Windows and Linux apps can also show it in a window of its own, which names the layer the alerts go to). Choose the kind of event and fill in its details:

Event	Details
Follower	the user name
Subscriber	the user name, the tier and the number of months
Donation	the user name, the amount, the currency and a message
Raid	the user name and the number of viewers

The simulator keeps a history of the last 20 alerts it sent; pick one to send it again.

What the overlay receives

Each test alert reaches the page the way third-party alert widgets expect their events, and as a plain window.postMessage for a page of your own, so most alert boxes react as they would to a real event.

For a quick check with nothing set up, Use Built-in Test Alert Page points the selected web overlay at the app’s own test page: an animated alert that plays a chime on every alert you send.