“App Lock – Lock Apps, Password” (sometimes just called App Lock) is an Android utility app that helps you protect other apps on your phone using a password, pattern, or fingerprint. It’s developed by InShot Inc. and has been downloaded over 50 million times.
The core idea is to give an additional layer of security beyond your phone’s regular lock screen, so your private apps, photos, and data stay safe even if someone else has your phone unlocked.
Key Features of App Lock
Here are some of the most important and useful features of this app, based on its description and user documentation:
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Multiple Lock Methods
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You can lock apps using password (PIN), pattern, or fingerprint. (Google Play)
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There’s also a “knock code” option according to the Play Store description. (Google Play)
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It supports an invisible pattern so someone looking over your shoulder can’t easily guess your pattern. (Google Play)
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Intruder Selfie
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If someone tries to open a locked app and enters the wrong password, the app takes a photo of that person using the front camera. (Google Play)
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This can help you see who is trying to access your apps without permission.
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Photo & Video Vault
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The app lets you hide photos and videos by encrypting them into a secure “vault” within the app. (Google Play)
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Only someone with the right lock method can access these hidden files.
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Lock All Types of Apps
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You can protect social media apps (like WhatsApp, Messenger, Instagram), system apps (like Settings), and practically any other app on the phone. (Google Play)
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It can also detect newly installed apps and lock them with one click. (Google Play)
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Re‑lock Timing
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You can configure how soon the app should lock again after it's been unlocked (“re-lock time”). (Google Play)
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This helps balance usability and security.
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Advanced Protection / Disguise
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The app can hide itself from the recent apps list so others won’t notice it’s running. (Google Play)
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You can also change the app’s icon to disguise it (for example, make it look like a calculator). (Google Play)
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Random Keyboard
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When entering PIN/password, the keyboard layout can be randomized. This helps prevent someone from guessing based on fingerprint smudges or observing your keystrokes. (Google Play)
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Password Recovery
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If you ever forget your lock password, you can reset it through security questions that you set up earlier. (Google Play)
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Themes and Customization
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There are themes for the lock screen, so you can personalize how the lock interface looks. (APKPure.com)
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You can also use your own photos as a background for the lock screen.
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Permissions and Privacy
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The app requests All Files Access permission in order to hide your private photos/videos in the vault. (Google Play)
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It also asks for Accessibility permission to improve locking behavior and speed. (Google Play)
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According to the developer, these permissions are used only for their intended security features, not for harvesting personal data. (Google Play)
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Pros of Using App Lock
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Extra Layer of Security: Even if someone unlocks your phone, they still need a separate code or fingerprint to access certain apps.
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Versatility: Multiple lock methods make it flexible — you can use what’s most convenient for you.
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Privacy for Media: The photo & video vault is a strong feature to protect sensitive media.
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Intruder Detection: Intruder selfie gives you visibility into who’s trying to snoop.
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Customizable: Themes, disguise icons, and custom lock timing make the app more user-friendly and less obvious.
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Lightweight: According to reviews, it doesn’t heavily drain battery or slow down the phone (though this depends on device).
Cons / Risks / Considerations
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Ads: Many users note that the free version has ads, which can be annoying. (Google Play)
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Permission Risks: It requires sensitive permissions (file access, accessibility). If not from a trusted source, such permissions can be misused. (Always download from official app stores.)
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App Might Be Killed: If your phone’s task killer or strong battery optimizer is active, it might kill App Lock or reduce its effectiveness. (Some users report that locked apps are not always locked after reboot.)
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Forgot Password: While there is a recovery option, forgetting your password still brings risk; if not set properly, you might lose access.
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Not Full System-Level: Third-party app locks (like this) sometimes can’t fully replicate system-level protection, depending on Android version and manufacturer optimizations. (Reddit)
Why Do People Use It?
Here are some common use-cases / scenarios where App Lock becomes really helpful:
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You lend your phone to friends or family and want to make sure they can’t access certain apps (chats, banking, social media).
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You have sensitive or private photos/videos that you don’t want others to accidentally open.
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You want to prevent kids from messing up settings, deleting things, or making unauthorized purchases.
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You want to track if someone tries to access your apps without permission (intruder selfie).
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You just feel more secure knowing there’s a second layer of protection for personal data.
How to Use App Lock — Basic Steps (in Simple Terms)
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Install the App
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Go to Google Play Store, search “App Lock – Lock Apps, Password” (by InShot Inc.) and install it. (Google Play)
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Set Up a Lock Method
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Open App Lock → go to Settings → choose PIN, Pattern, Knock Code, or Fingerprint.
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If you choose pattern, you can enable “invisible pattern” so others can’t see the drawing path.
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Select Apps to Lock
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The app will show a list of all your installed apps. Toggle on the ones you want to protect (e.g., WhatsApp, Gallery, Settings, etc.).
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Enable Intruder Selfie (Optional)
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In App Lock’s settings, enable the “Intruder Selfie” feature so that if someone fails to unlock, their photo is taken.
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Set Re-lock Time
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Choose how quickly apps should re-lock: immediately, after exit, or after a custom delay.
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Customize
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Pick a theme or background for the lock screen.
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If you like, change the App Lock icon so it looks like another app (disguise).
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Grant Permissions
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Allow All Files Access so the app can hide photos/videos.
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Allow Accessibility permission to improve performance and locking reliability.
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Recover Password (If Needed)
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Set up security questions or a recovery email in the app, so you can reset your lock if you forget it.
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Comparison with Other App Lock / Privacy Tools
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According to Android Authority, good app locking apps support fingerprint, pattern, random keyboard, and even intruder alerts — and they highlight AppLock as one of the top options. (Android Authority)
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Unlike built-in OEM app lock features (which some phone makers provide), this app works on a wide range of Android devices. For example, some Android skins don’t include native app-locking, so a third-party app is needed. (The Last Tech)
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There are other similar apps, but not all have the combination of features — intruder selfie, vault, random keyboard, disguise, etc. — that App Lock provides.
Safety Tips When Using App Lock
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Download from trusted sources: Use Google Play or other trusted stores; avoid shady APKs to reduce risk.
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Keep recovery options ready: Set security questions or recovery email so you don’t lock yourself out.
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Be careful with permissions: Since the app asks for file access and accessibility permission, make sure you understand why.
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Monitor battery / task killer behavior: If your phone has aggressive battery-saving or task killers, whitelist App Lock so it keeps running.
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Update regularly: Keep the app updated to benefit from new security features and bug fixes.
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Use in combination with phone lock: Don’t rely only on App Lock — also keep your main phone lock (PIN, fingerprint) active.
Final Thoughts
“App Lock – Lock Apps, Password” is a very useful and powerful tool for anyone who wants more privacy and control over their mobile apps. With its variety of lock types, the ability to hide media, intruder detection, and customizable features, it offers a robust second layer of security.
However, like all security tools, it’s not perfect. There are trade-offs: permissions, ads, and possible issues with battery optimization. But if used properly — especially with careful setup — it can greatly enhance your phone’s privacy.
If you care about keeping your private apps, photos, and messages safe — especially from snooping friends, kids, or casual phone borrowers — this app is definitely worth considering.