Question 1

What is NFC?

Accepted Answer

NFC stands for Near Field Communication — a short-range wireless technology that lets two devices exchange data by touching or being held within a few centimetres of each other. It's the same technology used in contactless payments (like Apple Pay and Google Pay), hotel key cards, and public transport passes.

NFC tags are small, inexpensive stickers or cards that contain a tiny chip and antenna. When you tap an NFC-enabled phone against one, the phone reads whatever is stored on the chip instantly — no app to open, no camera to point. SentinelTag uses this to store a unique ID on each tag, which the app uses to retrieve your data securely from the cloud. The result: tap a tag, see the information — in under a second.

Question 2

What do I need to use SentinelTag?

Accepted Answer

An Android phone with NFC support, blank NFC tags (NTAG213 or NTAG215 work well — wristbands, lanyard cards, or keyrings), and a SentinelTag account. Download the app, create an emergency profile, write to a tag, and set your authorised responders. The whole setup takes minutes.

Question 3

What's the difference between a tag in the app and a physical NFC tag?

Accepted Answer

They are two separate things that work together.

A tag in the app is a profile — it holds all the information about a person: their name, emergency contacts, medical notes, and access settings. You create and manage this in the SentinelTag app.

A physical NFC tag (a wristband, lanyard card, or sticker) is just a tiny chip that stores a unique ID. When you write a tag in the app, you tap your phone against a blank physical tag to link that ID to your profile.

The key point: one app profile can be written to as many physical tags as you like. So if someone needs a wristband at home and a lanyard card at school, you write the same profile to both — and both will pull up the same information when scanned.

Question 4

Do I need an internet connection to scan a tag?

Accepted Answer

You need a connection to view the tag's data, since the NFC tag only stores a unique ID — the actual content is fetched from our secure servers. Scanning itself takes less than a second on any mobile data connection.

Question 5

Which NFC tags should I buy?

Accepted Answer

We recommend NTAG213 tags for most use cases — they're inexpensive and widely available. NTAG215/216 work too. Any tag that supports ISO 14443-3A and can store a short URL or UUID will work.

Question 6

Why does my account need to be activated?

Accepted Answer

New accounts require activation before they can access tags. This prevents unauthorised users from accessing sensitive data. Spend 1 credit to activate your account for 30 days and unlock your first 2 tag slots.

Question 7

How do I give someone access to one of my tags?

Accepted Answer

Open the tag in the app, scroll to the Access section, and enter their email address. If they already have an account they get access immediately. If not, they'll receive an invitation email and get access as soon as they register.

Question 8

Can I share a tag with my whole team at once?

Accepted Answer

Yes — create a Group in the app, add your team members, then share a tag with that group. All current and future group members will have access.

Question 9

What is global access?

Accepted Answer

Global access allows members of an approved emergency response organisation — such as a police force, ambulance service, or NHS team — to scan any SentinelTag, regardless of who owns it. This means a paramedic or officer responding to an incident can immediately access critical information about a vulnerable person they have never encountered before.

Global access is restricted to genuine emergency services and is only granted after a vetting process. It is not available to care homes, schools, or other support organisations — those teams use private groups to access the tags belonging to the people in their care. Individual users cannot apply for global access.

Question 10

What is an Organisation account?

Accepted Answer

An Organisation account lets a team — such as a care home, school, or emergency service — manage their SentinelTag members centrally. The organisation owner can invite members with a unique PIN, manage access, view who has scanned which tags, and handle billing in one place.

Organisation billing is a monthly subscription at £1.99 per member per month, with reduced rates for larger teams.

Question 11

How do I join an organisation?

Accepted Answer

Your organisation administrator will generate an invite PIN for you. Enter it during registration, or from the Account section if you already have an account. Some organisations require an additional identifier — such as a collar number or GMC registration — when joining.

Question 12

Can emergency services get access to all tags?

Accepted Answer

Yes — through the global access programme, which is available to genuine emergency response organisations such as police forces, ambulance services, and NHS teams. Once approved after vetting, all active members of that organisation can scan any SentinelTag.

Care homes, schools, and similar organisations do not need global access — they only ever need to view the tags belonging to the people in their care. These teams should use a private group, which gives their staff access to exactly those tags and no others.

Access is subject to activity checks; members who have not used the app recently are automatically suspended until they log back in.

Question 13

What are credits used for?

Accepted Answer

Credits unlock access to the app — for yourself or someone else.

Your first credit activates your account: you get 30 days of access and 2 permanent tag slots to start creating profiles.

Each additional credit you spend is your choice — either extend your access by another 30 days, or add 2 extra tag slots for 30 days. Extra slots let you create additional profiles; when the 30 days are up the extra slots expire and those tags become inactive, but your data is kept. You can re-activate up to 2 expired tags at once by spending another credit.

You can also donate credits to another user or use them to activate a colleague's account. Credits can be gifted from the Account screen in the app.

Credits can be bought individually (£2.99 each) or in bundles.

Question 14

Do unused credits roll over?

Accepted Answer

Yes — credits in your balance never expire. Any credits you have bought but not yet spent stay in your account until you are ready to use them.

Question 15

How do subscriptions work?

Accepted Answer

A subscription automatically adds credits to your balance each billing cycle — keeping your account active without you having to manually spend credits.

Your 2 permanent tag slots (granted on first activation) are unaffected by subscriptions. Extra tag slots purchased with a credit last 30 days regardless of your subscription status, and can be renewed at any time by spending another credit.

Question 16

What happens to my tag data if I stop using the app?

Accepted Answer

If your account becomes inactive (no credits spent for an extended period), your tag data will be automatically and permanently deleted after 90 days. You will receive email warnings at 30 days and again at 7 days before deletion. Spending a credit before the deletion date will cancel the deletion and restore full access.

Question 17

Can I get a refund?

Accepted Answer

One-time credit pack purchases can be self-refunded directly in the app within 14 days of purchase, provided the credits have not been spent. Go to Account → Billing History, find the purchase, and tap Refund — the refund is processed automatically through Stripe with no manual step required.

Subscription charges cannot be refunded. To stop future charges, cancel your subscription via the billing portal.

Once credits have been spent, the service has been delivered and those credits are non-refundable.

Question 18

Is my data encrypted?

Accepted Answer

Yes. Tag data is encrypted at rest using AES-256 before being stored in Firestore. Each tag has its own unique encryption key. Your data is never stored in plain text.

Question 19

What happens if I lose my phone?

Accepted Answer

Sign in on any Android device and your tags and access are restored immediately. You can also sign in on the web dashboard to review and manage your tags. We recommend enabling biometric login to prevent unauthorised access.

Question 20

How do I delete my account and data?

Accepted Answer

Go to Account → Delete account in the app, or sign in to your web dashboard and contact support. We will delete all your data within 30 days.

Question 21

Who can see what's on my tags?

Accepted Answer

Only you and the users or groups you explicitly grant access to. Admins in your organisation can see which tags exist, but tag data is encrypted and only readable by authorised users.

Question 22

Why NFC and not RFID?

Accepted Answer

NFC is actually a subset of RFID — but the distinction matters. Traditional RFID (used in retail, logistics, and access control) can operate at ranges of several metres, meaning a reader can scan a tag without the wearer's knowledge. NFC operates exclusively at 13.56 MHz with a maximum range of around 4 centimetres. For a safeguarding platform, that short range is a deliberate feature: a scan can only happen when someone physically holds their phone against the tag. There is no covert or remote reading possible.

NFC is also built into virtually every modern smartphone — no specialist hardware or separate scanner is needed. It uses standardised security protocols (ISO 14443, ISO 15693) and supports two-way encrypted communication. Standard long-range RFID readers cannot read NFC tags without special configuration, which provides an additional layer of security. The combination of ubiquity, short range, and strong security protocols makes NFC the right choice for sensitive personal data.

Question 23

Is there an iOS version?

Accepted Answer

An iOS version is in development and will be available via the App Store soon. Sign up to our newsletter or follow our case studies for release updates.

Question 24

Can I lock a tag so it can't be rewritten?

Accepted Answer

Yes — open the tag detail screen and choose Lock tag from the menu. This sets a permanent lock bit on the physical NFC chip. Note: this cannot be undone.

Question 25

What happens when a tag expires?

Accepted Answer

Expired tags cannot be scanned — anyone who tries will see an "expired" message. The tag and all its data are kept; nothing is deleted.

To re-activate an expired tag, open My Tags in the app and tap "Re-activate" on the expired tag. One credit re-activates up to 2 expired tags at once for another 30 days — you choose which ones. This means you are never penalised for letting a tag lapse; your data is always there waiting to be restored.

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