Browser guide — Mozilla Firefox
Keep your screen awake in Firefox
Firefox was the last major engine to ship the Screen Wake Lock API — it arrived in Firefox 126 (May 2024). On any current Firefox the tool just works; on older versions, this page is your fallback plan.
Support at a glance
| Platform | Support | Notes |
|---|---|---|
| Windows, macOS, Linux | Yes — Firefox 126+ | Visible, HTTPS tab required |
| Android | Yes — current versions | The tool detects support automatically |
| iOS | Yes — iOS 16.4+ | Firefox on iPhone uses WebKit — see Safari |
| Firefox 125 and older | No | Update, or use the OS-level fixes below |
Check your version via Menu → Help → About Firefox. Firefox updates itself automatically, so if you use it regularly you're almost certainly on 126 or newer.
Using the tool in Firefox
Same one-tap flow as everywhere else: choose a duration, press the button, keep the tab visible. Firefox releases the lock when the tab hides, and the tool reacquires when you return — you'll see the status switch to Paused and back.
Firefox-flavored quirks
- It's the newest implementation. Chrome and Edge have shipped wake lock since 2020; Firefox's version dates from 2024. In practice it behaves the same, but if you hit anything odd, updating Firefox is the first fix — the implementation keeps maturing.
- Linux desktops vary. Wake lock ultimately asks the desktop environment to inhibit screen blanking. Most modern desktops (GNOME, KDE) honor it; some minimal window-manager setups don't provide the inhibit service at all, in which case no browser can keep the screen on — use your power settings instead.
- Hardened anti-tracking setups. Strict fingerprint-resistance configurations can restrict some device APIs. If the request is refused, the tool shows a plain-language error rather than failing silently.
On an older Firefox that can't update
Locked to an ESR build or an old system package? The browser route is out, but the OS route always works: Windows, Mac and Android each have built-in settings that keep the screen on, no browser capability required.