How to set up Streamlabs alerts with a custom animation

1. Use the WEBM, not the MOV

The Alert Box is a browser-based widget: it runs inside a browser source, which means it can only play formats a web browser can play. Browsers play transparent .webm files, but they don't play ProRes .mov files at all. So for Streamlabs alerts (and other browser-based alert tools like StreamElements), upload the transparent .webm. The green screen .mp4 will play, but you'll see a solid green box. Every BRANDED.GG order includes the .webm in the Transparent Background folder.

2. Add the Alert Box to your scene

1. In Streamlabs Desktop, select your main scene and click + to add a source.
2. Choose Alert Box from the widgets and add it.
3. Move it to the top of the source list so alerts play above your game and camera.
4. Resize it to the area of the screen where you want alerts to appear.

Using OBS Studio instead? Copy the Alert Box widget URL from your Streamlabs dashboard and add it to OBS as a Browser Source. Treat that URL like a password — anyone with it can show alerts on your stream.

3. Upload your animation

1. Open the Alert Box settings — either from the source's settings in Streamlabs Desktop or from Alert Box in your Streamlabs dashboard.
2. Pick the alert type you want to change, for example Follows.
3. Find the image/video setting for that alert and upload your transparent .webm.
4. Set the alert duration to roughly the length of the animation (most of ours are 5 to 7 seconds) so it isn't cut off or left hanging.
5. Save, then repeat for subs, raids and any other alert types you want to customise.

4. Sort out the text and sound

The Alert Box adds its own message on top of the media — something like '{name} just followed!', where {name} is replaced by the viewer's name. Our animations already show your channel and a follow or subscribe moment, so choose a layout where the text sits above or below the animation instead of on top of it, and keep the message short. Our files are silent, so upload a sound in the alert's sound setting and set the volume so it's noticeable but doesn't drown out your voice.

5. Test before you go live

1. Use the test buttons (Test Follow, Test Subscription and so on) in Streamlabs to fire a fake alert.
2. Check it plays from the start, the background is transparent, and the text doesn't overlap the animation.
3. Do a short local recording to hear how loud the alert sound is next to your mic.

Fixing common problems

1. Nothing plays: you probably uploaded the .mov. Upload the .webm instead.
2. There's a black, white or green box: you uploaded the green screen .mp4, or the file was re-exported without transparency. Upload the original .webm.
3. The animation is cut off: increase the alert duration, or check the Alert Box source isn't cropped or too small.
4. The upload fails: the file may be over the size limit. Our .webm files are small, but if you've re-exported one, upload the original.
5. Alerts appear behind the game: move the Alert Box source above your game capture.

Prefer to trigger alerts yourself? Add the animation as a Media Source with 'Loop' unticked and play it with a hotkey — see our OBS guide. It's ideal for reminders like 'drop a follow' that aren't tied to an event.