NFC tags
Learn how EnaFeedback NFC tags work, what the trust token does, and how to write, verify and lock tags from the mobile app as an organization owner.
An NFC tag is a small chip stuck at a location that opens that location when a phone touches it. In EnaFeedback, the main purpose of NFC tags is to prove that field staff are really at a location. Besides the location address, the tag holds a hidden trust token. When the mobile app reads that token, the location counts as verified, and cleaning or control logs can be recorded with confidence.
NFC verification works only in the mobile app
NFC verification works only in the EnaFeedback mobile app. Reading the trust token, writing and locking tags, and NFC-verified cleaning, control and attendance logs all need the app. If someone taps a tag with a phone that does not have the app, the location opens in the browser; that visit is the same as a QR scan and does not count as verified. The app is coming soon to the App Store and Google Play.
Required role and prerequisites
- Writing tags is limited to the Owner role (the NFC settings permission belongs to owners only). Other roles, including Administrator, cannot write tags.
- The EnaFeedback mobile app (Android or iOS) on an NFC-capable phone. There is no NFC writer in the web panel.
- The location exists under Organization → Buildings.
- Blank, writable NFC tags.
Mobile app
The EnaFeedback mobile app for Android and iOS is in internal testing. For access, contact us at support@enainnovation.com or 0850 308 45 91 (also WhatsApp). See Mobile app for details.
What is on a tag
Each tag holds two records:
- Location address:
https://nfc.enainnovation.com/EF+ 4-character customer code + 6-character location code. On a tap, ENA Cloud redirects this address to your organization's EnaFeedback address. - Trust token: a 256-bit random value in a separate text record. The server stores only a hash (SHA-256) of the token, never the token itself, and compares it in a timing-safe way.
If the EnaFeedback app is installed on the phone, a tap opens the app. Otherwise, it opens the web page.
Verified and unverified taps
| Tap | Result |
|---|---|
| With the mobile app | The app reads the trust token. If it matches, the location counts as verified. |
| With a browser (no app) | The browser cannot read the trust token. A normal, unverified location session opens. |
For visitors this makes no difference; the visitor screen opens either way. For field staff, it is decisive.
Write a tag
Open NFC settings
Sign in to the mobile app with your Owner account and go to NFC settings.
Pick the location and save
Pick the location for the tag and start Save. Hold the phone near the tag. The app writes the location address and a fresh trust token to the tag.
Verify
Use Verify to read the tag back. This checks that the tag carries the right location and a valid token.
Lock if needed
Once the tag is in place and verified, you can use Lock to make it read-only.
Locking cannot be undone
A locked tag becomes permanently read-only and can never be written again. If you later want to use it for another location, you will need a new tag. Verify the tag before you lock it.
Locking stops anyone from overwriting the tag. If you do not lock it, you can rewrite the tag later; every save creates a new trust token.
The "Verification required" setting
The field team modules have two proof-of-presence settings:
- Verification required: cleaning and control logs are accepted only from location sessions opened by an NFC trust token or a live display QR code. A printed QR or an NFC tap in the browser is not enough.
- Fresh session required: the log must be written within 5 minutes of the scan.
Before you turn these on, make sure the locations have an NFC tag or a live display. Otherwise field staff will not be able to log work there.
Tips and common mistakes
- Always test a tag with Verify after you stick it in place.
- Place the tag where it is easy to reach but hard to remove.
- Tell field staff to tap the tag with the mobile app, not the browser.
- The server keeps one trust token per location. When you write a new tag for a location, tags written earlier for that location no longer match.
Related articles
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