How to Use Face Recognition to Unlock Apps

Face recognition has gone from being a tech curiosity to becoming one of the most used authentication methods on smartphones. But many users don’t know they can use Face ID or face recognition not just to unlock their phone, but also to protect individual apps. In this article I’ll explain how to configure and use face recognition to unlock apps on Android and iOS.

Table of contents

How face recognition works on smartphones

Before setting anything up, it’s worth understanding how your face recognition system works, because not all are the same.

2D face recognition (most Android phones): Uses the phone’s front camera to capture a 2D image of your face and compare it with the registered one. It’s fast but less secure, since it can be fooled with a photo.

3D face recognition (Face ID on Apple and some premium Android): Uses an infrared dot system that creates a three-dimensional map of your face. It works in the dark, is more secure, and practically impossible to fool with a photo.

On iPhone, Face ID (3D) can authenticate any app that supports it. On Android, it depends on the manufacturer’s customization layer.

Pro-tip: If your Android has 2D face recognition, use it as a convenience method but not as the sole security factor for banking apps. Always complement it with fingerprint or PIN, since 2D recognition can be vulnerable.

Using Face ID to unlock apps on iPhone

On iOS, Face ID is deeply integrated with the system and apps support it natively. Setting it up is very simple.

Set up Face ID:

1. Go to Settings > Face ID & Passcode.
2. Enter your passcode.
3. Tap “Set Up Face ID” and follow the instructions.
4. Scan your face by moving your head in a circle.

Use Face ID in apps:

1. Open the app you want to protect (banking, notes, messaging).
2. Go to the app’s settings.
3. Look for the “Face ID,” “Biometric authentication,” or “App lock” option.
4. Enable Face ID.

Apps that support Face ID:

• Banks (Chase, Wells Fargo, Revolut, N26, etc.).
• Apple Wallet (payments).
• Apple Notes.
• iCloud Keychain passwords.
• Messaging (WhatsApp, Telegram, Signal).
• Password managers (1Password, Bitwarden, LastPass).

Using face recognition to unlock apps on Android

On Android the process varies by manufacturer, but the logic is similar.

General setup:

1. Open Settings > Security > Face recognition (or Biometrics).
2. Register your face following the instructions.
3. Enable face recognition as an unlock method.
4. Open the app you want to protect and look for the biometric security option.

On Samsung: Settings > Biometrics and security > Face recognition. Samsung allows using face recognition to unlock the “Secure Folder” and compatible apps.

On Xiaomi/HyperOS: Settings > Password & security > Face recognition. Xiaomi offers a “Second password” for apps that allows protecting individual apps with your face.

On Google Pixel: Settings > Security > Face Unlock. App integration depends on each application.

Comparison: face recognition vs fingerprint for apps

Both biometric methods have their advantages. Let’s see when each one makes sense:

My personal recommendation: use face recognition to unlock your phone (more convenient) and fingerprint for banking and payment apps (more secure on most Android). On iPhone, Face ID is secure for everything.

Pro-tip: If you wear glasses or grow/shave a beard, register your face with and without glasses, with and without beard. This significantly improves the recognition rate. On iPhone you can register an “alternate appearance” in Settings > Face ID & Passcode.

Common mistakes when using face recognition in apps

I’ve seen plenty of people get frustrated with face recognition over issues that take two minutes to fix. Here are the most common ones:

Face recognition doesn’t detect your face:

• Make sure you have good frontal lighting (not backlit).
• Clean the front camera — you’d be surprised how often a greasy fingerprint ruins recognition.
• If you got new glasses or changed your hairstyle, re-register your face.

The app doesn’t offer Face ID:

• Check that the app is updated to the latest version.
• On iOS, go to Settings > Face ID & Passcode > Other services and verify the app is enabled.
• Some apps only support Face ID in their premium version or with certain features enabled.

Face recognition is slow:

• On 2D Android, recognition depends on processor performance. If your phone is heavily loaded, it takes longer.
• Restart your phone if the problem persists — sounds silly, but it works half the time.

Face recognition fails with a mask:

• On iPhone with iOS 15.4+, Face ID can work with a mask if you enable the option in Settings > Face ID & Passcode > Face ID with Mask.
• On 2D Android, masks are a problem. Use fingerprint as an alternative.

Privacy and face recognition: what you should know

Face recognition isn’t just used to unlock apps. It also raises important privacy questions that many users overlook.

Where is your face data stored?

• On iPhone, Face ID data is stored exclusively on the device’s Secure Enclave. Neither Apple nor any app can access that data.
• On Android, it depends on the manufacturer. Data should be stored locally on the device’s security chip, but some budget manufacturers don’t have a dedicated chip.

Can apps access your face data? No. When an app uses Face ID or face recognition, the system simply tells it “yes, authentication was successful.” The app never receives your face image or 3D map.

What about the photos I take? Face recognition for unlocking apps is completely separate from face detection in photos. Google Photos or Apple Photos can identify faces in pictures, but that has nothing to do with the biometric authentication system.

Pro-tip: If you’re concerned about privacy, periodically review which apps have permission to use biometrics. Go to Settings > Privacy on iOS or Settings > Security on Android and check the list.

FAQ: Frequently asked questions

Is face recognition secure for banking apps?

It depends on the type. Apple’s 3D Face ID is extremely secure and banks accept it without issue. Android’s 2D face recognition is less secure and some banks don’t allow it as the sole authentication method.

Can I use face recognition if I wear glasses?

Yes, but register your face with your glasses on. If you alternate between glasses and contacts, register both versions. Apple’s Face ID is particularly good at recognizing faces with glasses.

What if my face changes a lot (makeup, surgery, aging)?

Modern systems adapt to gradual changes. For drastic changes (significant surgery), you’ll need to re-register your face. Face ID continuously adapts to minor changes like aging.

Can I use fingerprint and face recognition at the same time?

Not for the same app at the same time, but you can have both methods configured in the system and use whichever you prefer each time. Some users use Face ID for the phone and fingerprint for apps.

Conclusion

Using face recognition to unlock apps is one of the most underrated conveniences of modern smartphones. On iPhone with Face ID it’s a seamless experience: fast, secure, and widely supported. On Android, the experience depends on the manufacturer, but most offer decent options. Set it up now, protect your sensitive apps with biometrics, and enjoy the speed of unlocking your bank or notes just by looking at the screen.