How to Program an NFC Tag: Step-by-Step Guide

Programming an NFC tag sounds like technical work — but with the right apps, it takes less than a minute. This guide explains what tools are needed, what formats are available, and what to watch out for with NFC business cards specifically.

What does "programming an NFC tag" actually mean?

An NFC chip (also called an NFC tag) is a passive data store. It often arrives empty or pre-programmed. "Programming" means writing new data to the chip — for example a URL, a contact card, or text. This happens contactlessly via magnetic field, from an NFC-capable smartphone.

The chip itself has no software, no operating system, no "programming language." It stores raw data in NDEF format (NFC Data Exchange Format) — an open standard that any NFC device can read.

What do I need to program a tag?

• An NFC-capable smartphone — iPhone 7+ with iOS 13+ or an Android device with an NFC chip (built into virtually all smartphones since 2019).
• An NFC writing app — recommended: "NFC Tools" (free, for Android and iOS). Alternative: "NXP TagWriter."
• The NFC chip — either a loose sticker tag or embedded in a card.

Step by step: writing a URL to an NFC tag

1. Open NFC Tools.
2. Select "Write" → "Add a record."
3. Choose "URL/URI" and enter the desired address (e.g. https://www.example.com/my-profile).
4. Tap "Write / 1 task." The app asks for the chip.
5. Hold the smartphone close to the chip (1–3 cm distance) — the write takes under a second.
6. Done. Tapping the chip now opens the entered URL.

Step by step: writing a vCard to an NFC tag

A vCard contains contact data directly in NDEF format, without an external URL:

1. NFC Tools → "Write" → "Add a record."
2. Select "Contact" or "vCard."
3. Enter name, phone, email, website, and address as needed.
4. "Write" → hold chip → done.

Important: vCards take more storage space than plain URLs. With an NTAG215 chip (540 bytes), there is enough room for a compact vCard with a few fields; vCards with many fields, long addresses, or UTF-8 special characters can be too large.

URL or vCard — what is better for business cards?

For NFC business cards, the URL solution is almost always recommended:

• The profile behind the URL can be updated at any time (new number, new job, new photo) — without rewriting the chip.
• The profile can show more content than a vCard: portfolio, booking calendar, multiple links, images.
• Analytics are possible: you can see how often the profile has been accessed.

The vCard is useful when internet access may not be available (e.g. trade fairs abroad without roaming) or when data transfer without a server is preferred.

Setting write protection — when is it useful?

To prevent the card from being reprogrammed by others, you can set password protection on the chip. In NFC Tools: "Other functions" → "Password protect." After this, the chip can only be rewritten with the password.

Note: Setting write protection without noting the password makes the chip permanently read-only. For business cards, write protection is optional but recommended if the card is publicly accessible (e.g. as a table stand).

Reprogramming Glastrix cards

All Glastrix NFC business cards (NTAG215) arrive without write protection and can be reprogrammed with NFC Tools. They are delivered already programmed with the customer's chosen profile. If you want to change the URL later — for example after changing jobs — you just need an app and a minute.

For those who prefer not to deal with technical details: the digital profile behind the URL can simply be updated on the server, without touching the card. The chip stays, the card stays — only the content changes.