Store on the tag, or store on a server?
The most consequential decision in any deployment, and it is taken before the tags are ordered. On the tag means offline and permanent. On a server means changeable, unlimited and dependent on coverage. Everything else about the project follows from which one you pick.
Two different objects
A tag holding content is a small permanent document. A tag holding a link is a pointer to a document that can change.
They look identical, they cost the same, and they behave nothing alike once deployed. Choosing between them is choosing whether the deployment is editable.
The case for the tag
It works with no network. That is the argument, and where it applies nothing else competes.
It also has no dependency. No server to keep running, no domain to renew, no hosting bill in five years. A tag written today still works when the organisation that wrote it has moved on, which matters for equipment labels and long lived installations.
And nothing is requested from anyone. The content arrives from the object in the visitor's hand, so no request is made and no server learns that a tap happened. Where that discretion matters, it is a real property rather than a marginal one.
The case for the server
The content can change after deployment. This is the argument, and it is decisive far more often than people expect at the planning stage.
Every deployment contains a mistake that is discovered later: a wrong number, a moved page, a campaign that ends. On a server it is a five minute fix, and on a tag it means collecting the tags.
Capacity also stops being a constraint, since the pointer is short and what it points at is unlimited. And one identical write can serve an entire batch when the chip mirrors its identifier, which removes the per tag encoding step altogether.
How to decide
Ask one question: will there be a network where people tap?
If the honest answer is no, or not reliably, the content goes on the tag and you size the chip accordingly. A field, a cellar, a venue at capacity, a ship.
If the answer is yes, put a short address on your own domain and hold everything else on the server. This is the right answer for the large majority of deployments, and the ones that regret it are the ones that assumed coverage they did not have.
The hybrid works too, and is underused. Write the essential information as text and a link alongside it, so the tap gives something useful offline and something richer when there is coverage. It costs memory and it removes the worst failure mode.
Frequently asked questions
Can I change my mind later?
Only if the tags are unlocked and physically reachable. That is the practical asymmetry: moving from a link to on tag content is easy to plan for, and rewriting a thousand installed tags is not.
Does a link mean my visitors are tracked?
It means a request reaches your server, which is what any web page involves. What is recorded is your decision, and holding content on the tag avoids the request entirely.
Which is more reliable?
On the tag, if reliability means working with no coverage. On the server, if it means still being correct in two years.
What about a QR code alongside?
It costs nothing, it is readable by phones without NFC, and it makes the link visible to people who do not know to tap. For public deployments it is close to free insurance.