Guide · Android

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How to block apps with an NFC tag on Android

The short answer

Enrol an NFC tag as your key in MassBlocker (Pro), then lock your apps. The lock screen then accepts only that tag, or your PIN if you set one. Stick the tag somewhere inconvenient: the walk is the friction.

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Updated 9 October 2026

What you need

An Android phone with NFC. Not every phone has it. MassBlocker tells you if yours doesn't, or if NFC is turned off. No NFC? Use a QR code (Free) or your charger (Pro) instead.
One NFC tag. A sticker or card tag; NTAG stickers are common and sold in packs. MassBlocker only reads the tag's ID, so nothing is written to it.
Somewhere to put it that takes effort to reach. This is the part that matters.
MassBlocker Pro. NFC unlock is a Pro feature. Pro

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Enrol your tag (Pro)

Step 1: Turn on NFC.
Find it in your phone's settings, if it's off.
Step 2: Open MassBlocker, then Unlock policy.
Under Pro controls, in Unlock method, choose NFC tag.
Step 3: Hold the tag to the back of your phone.
MassBlocker remembers that tag as your unlock tag. To change it later, use “Use a different tag”.
Step 4: Test the tag once.
Before you rely on it, find where your phone's NFC reader sits on the back.
Step 5: Stick the tag where you decided.
Then leave it there.
Step 6: Set a PIN, and give it to someone you trust.
If the tag goes missing, the PIN is the other way past an NFC lock.
Step 7: Tap Lock now.
To open your blocked apps, go and tap the tag.

Choose your key before you lock: changing the unlock method ends a lock that's already running.

Where to put the tag

The tag is not the mechanism. The distance is. A tag on your desk gives you a very tidy version of no blocker at all.

Another room
The kitchen, if you work in the bedroom. Far enough that going there is a decision.
Inside or behind something
The back of a cupboard door, under a shelf. Out of sight, it stops reminding you.
Somewhere you'd need shoes for
A balcony, a stairwell, the front door. The strongest option. If you catch yourself moving the tag closer, that's a sign it was working.

One tag, one place. Moving it around undoes the habit you're building: unlocking should have a fixed, slightly annoying cost.

How an NFC lock works

A timer asks you to wait. A tag asks you to move. The second is much harder to do without noticing that you're doing it.

No wait before the first unlock. Tap Lock now and the lock screen shows “Tap your tag to unlock”. The walk to the tag is the friction.
Only your tag works. A different tag, even one from the same pack, gets “That isn't your enrolled tag.” The PIN, if you set one, also opens the lock.
No QR fallback. In NFC mode the lock screen has no Scan button. For a backup, set a PIN and give it to someone else.
Auto-relock Pro (the app calls it Recurring cycles): a tap opens your apps for a usage window you choose. Then they lock again, and each re-lock waits your minimum lock time before the tag works again.

A timer also lives on the same phone you're trying to put down. The tag sits outside that argument: the answer is on the wall in another room. Strict mode (Pro) puts MassBlocker's settings behind the PIN too, so changing your key in the middle of a lock needs it. Strict mode is a strong deterrent, not an unbreakable jail — on stock Android a determined user can disable the service.

FAQ

Questions

Is there a wait after I tap the tag?

Not for the first unlock: a tap on your enrolled tag opens your apps straight away. With auto-relock on (Pro), each re-lock waits your minimum lock time before the tag works again.

What tags work?

Common NFC sticker and card tags, such as the NTAG stickers sold in packs. MassBlocker reads only the tag's ID, so nothing is written to the tag and its storage size doesn't matter. If your phone can read the tag, you can enrol it.

Can someone bypass it with another tag?

Not from the lock screen: it accepts only the tag you enrolled, or your PIN if you set one. Without strict mode, you can enrol a different tag in Unlock policy during a lock; strict mode (Pro) puts that behind your PIN.

Can I use a tag and a QR code together?

No. You choose one unlock method before you lock. In NFC mode the lock screen accepts only your tag, or your PIN if you set one. For a backup, set a PIN (Pro) and give it to someone you trust.

What if I lose the tag?

Use your PIN on the lock screen, if you set one. Then enrol a new tag in Unlock policy with "Use a different tag". Without strict mode, changing the unlock method also ends a lock that is running; with strict mode on, that needs the PIN.

Does NFC need to stay on?

It needs to be on when you tap. If it's off, MassBlocker asks you to turn it on in Settings before the tag will work.

What if my phone doesn't have NFC?

Use a QR code instead (Free). It works with your phone's camera and gives you the same walk-across-the-room friction. With Pro, your charger can be the key too: plug in, then tap Unlock.

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MassBlocker, the app in this guide

NFC is one of the ways MassBlocker can end a lock. Scan a QR code you hid (Free), or with Pro, type a 3-word code, tap an NFC tag, or plug in your charger and tap Unlock.

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