Should we lock our NFC tags after writing them?
For product, asset and public-facing tags, yes. An unlocked tag can be rewritten by anyone with a phone and a free app.
Start here
For most deployments, yes. An unlocked tag can be rewritten by anyone who taps it with a phone and a free app. On a product or a poster, that means a stranger can point your customers somewhere else.
Options
- Permanent lock. The content becomes read-only for good. Simple, but you cannot fix a typo later.
- Password protection. Some chips allow writes only with a password. Useful when you need to update tags in the field.
- Signed content. The tag carries data your app or server can verify, so a tampered tag is spotted.
When to leave tags open
Internal test batches, or tags you rewrite as part of a process, may need to stay writable. Keep them out of public reach and track them separately.
Test before you lock
Write a small batch, tap each one on two or three different phones, then lock. Locking a whole box with the wrong content is a common and avoidable mistake.
Locking status is one line on our tag audit checklist. Related: can NFC tags be cloned?
Check every tag, card and reader before someone else does