What can a smartphone actually do with NFC?
Read tags and behave as a card. What happens after a tag is read is decided by the operating system rather than by the tag, and the two platforms decide differently. That gap, rather than the hardware, is where public deployments come unstuck.
The phone is the reader
When you tap a tag, the phone produces the field, powers the tag and reads it. The tag has no battery, no initiative and no choice in the matter.
A phone also works the other way, behaving as a card that answers a terminal. That is what happens when you pay, and it uses the same antenna through an entirely different path.
Both capabilities are documented by the platform owners. Android publishes its NFC guide, and Apple publishes Core NFC.
The platform decides what happens
A tag holds a record and a declaration of what that record is. Everything after that belongs to the operating system: whether it looks for tags at all, which application receives the content, and whether anything opens without the user confirming.
Android answers those questions through a dispatch system that ranks candidates and hands the tag to one of them, and from Android 17 it asks the user before opening a web link.
iOS answers them more narrowly, with fewer record types acted on, a confirmation step in the background path, and a hardware line below which an application must be opened first.
Neither is wrong. They are different products, and a tag written without knowing which rules apply will satisfy one and disappoint the other.
Where the differences bite
| Question | Why it matters |
|---|---|
| Which record types are acted on? | Content that is inert on one platform |
| Does the phone look for tags unprompted? | Whether a tap works from a locked phone |
| Is there a confirmation step? | A tap that appears to do nothing |
| Which app receives the tag? | The wrong application opening |
A web address is the content least affected by all four, which is why it is the safe answer for anything the public will tap.
Testing that means something
Test on both platforms, not on the phone in your pocket. A deployment validated on one is a deployment validated for half its audience.
Test on the oldest hardware you can find. Margin hides faults, and your visitors have less of it than you do.
Test the outcome rather than the read. A tag that is detected and does nothing has passed the wrong test, and that is the most common way a deployment ships broken.
And let someone who has never seen the tag try it. Their gesture is the requirement, not yours.
All guides in this section
Android
- How do you turn NFC on and off on Android?
- What does Android do automatically when you tap a tag?
- What is Android's tag dispatch system?
- Where does Android show what a tag contains?
- Can an app take priority over the system on tap?
- How do you stop Android opening a tag automatically?
- Can Android write every kind of tag?
- Does Android read tags with the screen off?
- Which Android versions support which NFC features?
- Why do some Android phones read tags others cannot?
- Can Android emulate a card without a secure element?
- Does a work profile or an MDM affect NFC?
iOS
- Which iPhones can read NFC tags?
- Which iPhones can write NFC tags?
- Why must an NFC app be launched manually on iPhone?
- Why does an iPhone show a scan sheet when an app reads a tag?
- How do you read a tag on iPhone without an app?
- Does the iPhone read tags when locked?
- Why does the iPhone show a banner instead of opening the link?
- Why does iOS refuse some Wi-Fi and app records?
- Does iOS support tag locking and passwords?
- Can an iPhone emulate an access badge?
- What changed for NFC across recent iOS versions?
- Can an iPad or an Apple Watch read NFC tags?
Antenna and hardware
- Where is the NFC antenna on a phone?
- Why is a phone's NFC antenna so small?
- Do foldable phones behave differently with NFC?
- Why does NFC stop working after a phone repair?
- Do rugged phones read NFC tags reliably?
- How many tags can you read in a row on a phone?
- How do you choose phones for an NFC deployment?
- Are external NFC readers worth it for phones?
- What does a dedicated reader add over a phone?
- How do you tell a visitor where to hold their phone?
Background reading and phone behaviour
- When is a phone actually listening for tags?
- Does background reading drain the battery?
- Does background reading work in aeroplane mode?
- Does NFC work without a SIM or mobile data?
- Does NFC work while the phone is doing something else?
- Why does the same tag trigger twice?
- How do you disable background reading?
- What permissions does an NFC app need?
- Does a phone keep a history of the tags it has read?
- Can NFC tags work as an accessibility aid?
Frequently asked questions
Can every phone with NFC read every tag?
Any phone with NFC reads a Type 2 tag. What varies is whether the operating system acts on the content, which is a separate question from reading.
Why does the same tag behave differently on two platforms?
Because each platform decides which record types to act on and how. The tag returns the same bytes and the systems make different decisions about them.
Is one platform better for NFC?
They differ rather than rank. Android is more permissive about content and background behaviour, and iOS is more predictable about what it will do.
What content works everywhere?
A web address. It is the record type handled most consistently across platforms and versions, and it moves the complexity to a page you control.