Your phone is already locked. So why would anyone want a second lock on WhatsApp or the gallery?
Because phones get handed around. A friend wants to see a photo or a child wants to play a game. A colleague may borrow it for a quick call. A fingerprint app lock lets you share the phone without sharing everything on it.
The good news is that you may not need to install anything. Many phones now ship with their own app lock. This guide compares those built-in tools with the best-known app lockers to help you pick what suits you.
What actually happens when you touch the sensor
An app lock sits between you and the app. When you tap a locked app, a lock screen pops up first. You scan your finger and the app opens.
The fingerprint itself never goes to the app lock. Android checks your finger inside secure hardware and only tells the app “yes” or “no”.
That is the same system your bank app uses. You can read more about it in our guide to biometric authentication.
There is one key difference between the two kinds of lock. A built-in lock is part of the phone’s software.
A third-party app lock has to watch which app you open and then jump in front of it. To do that it needs strong permissions. That matters later in this guide.
Check your phone first: the locks you already have
Before you download anything, look in your settings. The built-in options are free and carry no ads. They also don’t need extra permissions.
Android private space (Android 15 and later)
Private space is a hidden area for sensitive apps. You set it up under Settings > Security & privacy > Private space. It can use your fingerprint or a separate PIN.
When the space is locked, its apps stop running completely. They can’t send notifications or run in the background. You can even hide the space from the app drawer so nobody knows it exists.
There are trade-offs. Apps inside private space aren’t included in device backups. Google’s private space help page also notes that it skips your VPN and doesn’t support widgets.
Pixel’s new one-tap app lock (in testing)
Google is testing a simpler option on Pixel phones. In the Android 17 QPR2 beta you long-press any app and choose to lock it. After that it asks for your fingerprint or PIN each time.
It’s still in beta, and Google hasn’t said when it reaches everyone. Privacy Guides points out that it doesn’t encrypt the app’s data separately. It mainly stops someone who picks up your phone.
Samsung app lock fingerprint options: Secure Folder
Samsung’s main tool is Secure Folder. It’s a separate space protected by Samsung Knox, and it can unlock with your fingerprint. You can install a second copy of WhatsApp or your gallery inside it.
You can also hide the folder from the quick settings panel. Samsung notes in its Secure Folder guide that the folder has no direct backup. Move files out before you reset your phone.
What Samsung doesn’t have globally is a simple per-app lock. A Samsung community manager said in 2026 that one was being tested in One UI 8.5 beta. A stable release hasn’t been confirmed.
Xiaomi, Redmi and POCO
Xiaomi phones have a true app lock built in. Go to Settings > Apps > App lock. Pick a pattern first and then switch on fingerprint unlock.
Xiaomi suggests linking your Mi account. That way you can reset the password if you forget it.
Other Android brands
Many other makers include an app lock in their privacy settings. Search your Settings app for “app lock” or “app encryption”. The name changes from brand to brand.
Built-in locks aren’t flawless either. In 2017 a researcher showed that the OnePlus app locker could be opened from a launcher shortcut. OnePlus fixed it in an update.
How to lock WhatsApp with fingerprint
You don’t need an app locker for WhatsApp. WhatsApp added its own fingerprint lock for Android in 2019. Open Settings > Privacy > App lock (older versions call it Fingerprint lock).
For single chats there is Chat Lock. Locked chats move to a hidden folder and their notifications show only “new message”. You can also set a secret code that differs from your phone PIN.
A quick word for iPhone users
iPhone owners also have this built in. From iOS 18 you can long-press an app and choose Require Face ID or Touch ID. Apple’s lock or hide an app guide explains the steps.
When a third-party app locker makes sense
Sometimes the built-in lock isn’t enough. Your phone may be older than Android 15 or your brand may have no per-app lock at all.
Or you may simply want extras like intruder photos. That’s where app lockers come in.
Below are three well-known choices. We picked them on track record and transparency rather than star ratings alone. The figures come from each app’s Google Play listing in October 2026.
AppLock (originally DoMobile, now PIPS Tech)
This is the veteran of the group. It has over 100 million downloads and a 4.3 rating. Many people still know it by its old developer name, DoMobile Lab.
It locks any app with a PIN, pattern or fingerprint. It also has a photo and video vault and a random keyboard that stops people reading your PIN. You can hide its icon and open it through a dial code instead.
The catch is the business model. The app is free with ads. Its Play Store data safety section says it may share app activity with third parties.
AppLock – Fingerprint (SpSoft)
SpSoft’s app has over 50 million downloads and the same 4.3 rating. Its best-known feature is the applock intruder selfie. After a wrong attempt it snaps a photo or video of the person and can email it to you.
It also offers a fake error screen. Someone who opens your locked gallery sees a crash message instead of a lock. You can set different passwords per app and lock apps by time or Wi-Fi network.
Two cautions apply here. The listing showed no update since February 2025. Some reviewers also say that closing an ad can slip past the lock in the free version.
App lock inside a security suite
Some antivirus apps include an app lock. Bitdefender Mobile Security is one example. Its support page says its App Lock protects apps with a PIN or fingerprint.
This route suits people who already pay for a security app. You get one trusted company instead of a small ad-funded developer.
Features worth comparing
Most lockers offer the same basics. These are the extras that actually change your experience:
- Fingerprint and password app lock together. A backup PIN matters when your finger is wet or the sensor fails.
- Intruder photo. Handy for curiosity, but it uses your camera and stores faces of other people.
- Fake cover. A fake crash screen hides the fact that an app is locked at all.
- Uninstall protection. This needs device admin rights so nobody can simply remove the locker.
- Relock timing. Good apps let you choose whether to relock instantly or after the screen turns off.
Built-in lock or app locker: side by side
| Built-in lock | Third-party app locker | |
|---|---|---|
| Cost | Free, no ads | Usually free with ads or paid upgrades |
| Extra permissions | None | Accessibility, usage access, often device admin |
| Data sharing | Stays with your phone maker | Check the Play Store data safety section |
| Intruder photo | Rare | Common |
| Fake cover screen | No | Often |
| Hides notifications | Private space and Secure Folder do | Varies by app |
| Works on older phones | Depends on brand and Android version | Yes, on most Android phones |
| Survives a factory reset | No | No |
Which one suits you?
There’s no single best app lock fingerprint option for everyone. It depends on your phone and on who you’re hiding things from.
- You only want to protect WhatsApp. Use WhatsApp’s own app lock or Chat Lock. Nothing else is needed.
- You have Android 15 or later. Try private space first. It hides apps and blocks their notifications too.
- You have a Samsung Galaxy. Secure Folder is the official route for now. Watch for the per-app lock in future One UI updates.
- You have Xiaomi, Redmi or POCO. The built-in App lock already does the job.
- Your phone has no built-in option. A third-party locker fills the gap. Choose one with a clear privacy policy and recent updates.
- You want to catch a snooper. Only third-party lockers offer intruder selfies. Decide whether you’re comfortable with an app that can use your camera.
Think about who the lock is really for. A curious child is stopped by almost any lock. A determined person who knows your PIN is a different story.
The permission question nobody reads
To lock other apps, a third-party locker has to know what’s on your screen. Most ask for the Accessibility permission to do it. Both AppLock listings above say they use it only to spot which app you open.
That permission is powerful. It was built to help people with disabilities, so it can read screen content and tap buttons. Google’s Play policy on Accessibility makes apps explain clearly why they need it and get your consent.
Here lies the trade-off. You’re trusting one app to guard all your others.
A trustworthy locker is fine. A shady one has the keys to everything.
Safety habits that cost nothing
A few simple habits keep the risk low:
- Install from Google Play only. Unofficial copies are a favourite hiding place for malware.
- Read the data safety section. It shows what the developer says it collects and shares.
- Check the last update date. An app that hasn’t been updated in a year may not keep up with new Android versions.
- Keep a backup PIN you’ll remember. If you forget it, you may have to reset the locker or even the phone.
- Grant only what’s needed. A locker shouldn’t need your contacts or your location to lock apps.
Is a fingerprint really safer than a PIN?
This is where opinions differ. Fingerprints are fast and hard to shoulder-surf. Nobody can watch you type them.
But a fingerprint can be used without your full consent. Someone could press your finger to the phone while you sleep.
A PIN in your head is harder to take. We weigh these points in our look at biometrics pros and cons.
Many people use both. A fingerprint gives daily speed and a PIN acts as backup. Whether that balance suits you is your call.
Does your phone also offer face unlock? Our face vs fingerprint comparison may help you choose.
Quick answers before you lock anything
Does an app lock see my fingerprint?
No. Android checks your finger in secure hardware and only passes back a match result. The app lock never gets the fingerprint image.
Can I use a fingerprint and a password on the same app lock?
Yes. Almost every fingerprint app lock asks you to set a PIN, pattern or password first. The fingerprint is a shortcut on top of it.
Will locked apps still send notifications?
It depends on the tool. Private space stops locked apps completely and WhatsApp Chat Lock hides the message content.
Many third-party lockers let messages through. Look for a notification lock setting if that bothers you.
What if I forget my app lock PIN?
Built-in locks usually reset through your phone’s screen lock or your account. Third-party apps often use a security question or email. Set this up on day one.
Can someone just uninstall the app locker?
They can unless you turn on uninstall protection. That feature uses device admin rights. Built-in locks can’t be uninstalled.
Is there a fingerprint app lock for iPhone?
Yes, and it’s built in. Since iOS 18 you can require Face ID or Touch ID for most apps. Third-party lockers aren’t possible on iPhone.
What would you lock first?
A fingerprint app lock is a small thing. Yet it changes how relaxed you feel when someone borrows your phone.
Built-in tools are now good enough for many people. App lockers still fill the gaps on older phones and add a few extras.
So which side are you on? Would you trust one app with the keys to all your others for an intruder selfie? Or does a built-in lock do everything you need?
And is a fingerprint the right key at all? Only you know what’s on your phone and who you’re keeping it from.
Sources
- Google Android Help: Hide sensitive apps with private space
- Privacy Guides: Android will allow you to lock any app behind your fingerprint or PIN (August 2026)
- Samsung Support: What is the Secure Folder and how can I use it?
- Samsung Community: One UI 8.5 App lock feature
- Xiaomi Support: App lock
- WhatsApp Blog: Introducing fingerprint lock for Android (October 2019)
- WhatsApp Help Center: Turn chat lock on or off
- Apple Support: Lock or hide an app on iPhone
- Google Play Console Help: Use of the AccessibilityService API
- Google Play: AppLock by PIPS Tech and AppLock – Fingerprint by SpSoft
- Bitdefender Support: What is Bitdefender Mobile Security for Android?
- XDA Developers: The OnePlus App Locker feature can be easily bypassed (2017)
