What does Android do automatically when you tap a tag?
It reads the tag, works out what the content is, and starts whichever application is best placed to handle it. Up to Android 16, nothing stands between the tap and the action, which is the main behavioural difference from iOS and the reason Android feels more immediate. From Android 17, a tag holding a web link first shows an open link notification, and the link opens only when the user acts on it.
The sequence
The phone detects the tag, powers it and reads its content. It then examines the record to work out what the payload is.
With that answer it looks for an application willing to handle that kind of content, and starts it. The Android NFC guide describes this as the tag dispatch system.
A web address opens in a browser, from Android 17 once the user has acted on a notification. A phone number offers to dial. Text is displayed. The outcome follows from the record type rather than from the characters.
Immediate, up to Android 16
Up to Android 16, Android acts on the tag directly, and nothing asks whether you meant to tap it. From Android 17, the NFC basics guide says a tag holding a web link shows an open link notification instead, and the link opens only when the user acts on it.
Acting directly makes the experience fast, and it means a tag can send a phone somewhere with a single unconsidered gesture. It is the reason a tag in a public place deserves thought about what it points at.
It is also the clearest contrast with iOS, where a background read presents a notification that has to be tapped. For a web link the contrast now depends on the version: a deployment that feels instant on Android 16 shows an extra step on Android 17 as on an iPhone, and none of them is broken.
When a choice appears
If several installed applications claim the same kind of content, the system presents a chooser rather than picking for you.
That is normal behaviour and it surprises people, because a tag that opened a browser on a clean phone opens a menu on a phone with more applications installed.
It is also why testing on your own device is misleading. Your phone has unusual software on it, and a visitor's does not.
A chooser dismissed by accident looks exactly like a tag that did nothing.
When nothing happens
The phone reacts and then stops when the content gives it nothing to act on: an empty tag, a text record, or a record whose type declaration is missing.
Detection and action are separate steps, so a reaction followed by silence means the tag was read perfectly and the content was not actionable.
Reading the tag with a tool that reports record types settles this in seconds, and no amount of retrying the tap will.
Frequently asked questions
Why does my tag open a browser instead of an app?
Because a web address record is handled by a browser unless an installed application registers for that address. Both outcomes are normal.
Can I stop Android acting automatically?
Not globally in the way people expect. From Android 16 you can stop one app being started by tags, and from Android 17 a web link waits for the user on a notification. Beyond that, what you can control is what happens once your own application is in the foreground.
Why do I get a list of apps?
Several installed applications claim the same content type, so the system asks. It is normal and it is why testing on a typical device matters.
Does the tag decide which app opens?
It influences the decision through its record type, and a record naming an application makes that preference explicit. The system still decides.