If you install a screen lock app on Android 9 or higher, the first thing it asks for is the Accessibility permission (technically called Accessibility Service). This often makes users pause - it sounds broad and sensitive. This article explains exactly what the permission does, what it cannot do, and whether it is safe to grant it for the specific use case of locking your screen.
What Is the Android Accessibility Service?
The Accessibility Service is an Android system feature originally designed to help users with disabilities. It can:
- Perform actions on behalf of the user (tapping, scrolling, going back)
- Observe what is on the screen (for screen readers like TalkBack)
- Interact with UI elements in other apps
Because of these capabilities, Android warns you with a dialog whenever you enable an accessibility service. The warning says something like "This service can collect all text you type including passwords and payment information."
That warning is true for screen readers and some accessibility tools. But it is not relevant to what a screen lock app does.
What Does Turn Off Screen's Accessibility Service Actually Do?
Turn Off Screen uses the Accessibility Service for exactly one purpose: to programmatically execute the screen lock action - the software equivalent of pressing the power button.
In Android's API, this is the performGlobalAction(GLOBAL_ACTION_LOCK_SCREEN) call. It locks the screen and turns off the display. Nothing else.
The service in Turn Off Screen does not:
- Read what is on your screen
- Observe other apps
- Capture text you type (passwords, messages, etc.)
- Monitor your activities
- Send any data anywhere
You can verify this by checking the app's permissions in Settings → Apps → Turn Off Screen → Permissions. You will see no network access, no storage access, no location - only the minimum required to function.
Why Does Android Show a Scary Warning Then?
Android shows the same permission dialog for all accessibility services, regardless of what they actually do. Whether an app uses accessibility to read your entire screen or only to lock it, you see the same warning.
This is a limitation of Android's permission system: it cannot grant "partial" accessibility access. The warning is a catch-all designed for the broadest possible capability, not a description of what a specific app actually does.
The right approach is to look at the source of the app:
- Is it in the Play Store?
- Does it have many downloads and reviews?
- What does it actually request in its permissions list?
Turn Off Screen has over 5 million users and has been on the Play Store since 2017. Its codebase does the one thing it advertises: lock the screen.
How to Verify This Yourself
If you want to confirm that Turn Off Screen is not doing anything unexpected, you can check:
1. Check app permissions: Settings → Apps → Turn Off Screen → Permissions
You should see: No location, no contacts, no camera, no microphone, no storage access. The only sensitive item is the Accessibility service itself.
2. Check network traffic: If you have a firewall app (like NetGuard), you can block Turn Off Screen's network access entirely. The app will still lock your screen - because it has no reason to communicate with the internet.
3. Read the privacy policy: turnoffscreen.app/privacy - the policy states that no screen content, keystrokes, or personal data are collected. All user preferences are stored locally on your device.
The Accessibility Permission vs. Device Admin
On Android 8 and below, Turn Off Screen uses the Device Administrator permission instead of Accessibility. Device Admin has a narrower, more specific lock-screen capability built in - Android 8- devices do not support GLOBAL_ACTION_LOCK_SCREEN.
On Android 9+, Google added the accessibility-based lock screen action and recommended it as the correct approach for third-party lock apps. Turn Off Screen follows this recommendation.
What Happens If I Revoke the Permission?
If you go to Settings → Accessibility and disable Turn Off Screen, the lock button will stop working. Tapping it will prompt you to re-grant the permission.
The app will not crash, it will not delete any data, and no other functionality changes. You simply lose the ability to lock the screen through the app until you re-enable the service.
Should I Grant the Permission?
For a reputable, widely-used screen lock app like Turn Off Screen, yes. The permission is the only way Android allows third-party apps to lock the screen on modern versions of the OS. The capability is used for one action, and the app has a public privacy policy, millions of users, and Play Store visibility.
If you are ever unsure about any app requesting Accessibility access, the right questions are:
- What does this app actually need to do?
- Does the accessibility request make sense for that function?
- Does the app have network access, and if so, does it need it?
For Turn Off Screen: the function is locking the screen, the accessibility request makes sense, and the app has no reason to use network access (and in fact uses near-zero battery and data).
Summary
The Android Accessibility permission is a broad capability that sounds alarming because of how Android's warning dialog is written. For screen lock apps specifically, the permission is used only to perform a single system action - locking the screen - and nothing more. It does not enable the app to read your screen, capture input, or observe other apps.
Turn Off Screen uses this permission responsibly, has been audited implicitly by millions of users over many years, and gives you full transparency about what it does and does not collect.
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