Seritag is a trusted, professional
UK supplier of NFC Tags worldwide

What is an NFC tag ?

An NFC (Near Field Communication) tag is a small electronic item such as a label, disc tag, keyfob or card which can communicate wirelessly to transfer data without contact to an NFC reader, such as a mobile phone.

NFC tags are passive which means that they don't contain a battery or other power source and get all their energy from being in close proximity to the reading device - typically a mobile phone.

All tags contain three key elements - a tiny NFC microchip, a coil of wire which is the 'antenna' and a substrate such as a thin sheet of plastic to hold it all together.

The communication distance is short - typically 2-7 centimetres (1-3 inches) which makes NFC technology ideal for close range identification of specific items. As no battery or power source is required, NFC tags can be made thin and small, making them suitable for use in smart packaging, clothing, posters, wristbands, keyfobs and cards.

The amount of information that a tag can store is very limited, usually not more than this sentence. Therefore, tags are best suited to being the link to data (stored in the cloud or other website) rather than the data source itself.

Buying Tags

The first thing to consider is the difference between an NFC chip and an NFC tag. The NFC chip is the tiny microchip that all tags contain. This manages the communication and stores the data. Typical NFC chips are NTAG213, NTAG424, ST25TN01K. The NFC tag is the physical structure such as a sticker, disc tag, wristband, etc.

NFC Chip : For almost all use cases where the data is a web link or an ID, then the NTAG213 chip is the perfect all-round choice.

NFC Tag : There's a large number of different choices from wristbands to keyfobs, stickers to disc tags.

NFC Tag Authentication

The latest generation of advanced NFC chips, such as the NTAG424 or EM|Linq, can be used for anti-counterfeit protection. These authentication chips are more advanced than standard NFC chips (such as the NTAG213) and are able to generate unique security codes on each scan.

When the authentication chips are encoded, a secure key is stored on the chip as well as the URL/link. When the tag is scanned, the chip uses this key, along with the scan count, to generate a unique scan code. This code can be verified on the destination website or via an authentication server. The process is designed to be frictionless which means that no app or other software is required on the phone for this to happen - authentication tags can be scanned like any other tag.

Unlike standard NFC tags or QR codes which can be easily copied, these advanced tags provide a very high degree of confidence that tag - and therefore the object they are attached to - is original and genuine.

Authentication tags are now being used in a wide variety of applications such as luxury goods, collectables, specialist manufacturing, supply chain security, physical NFT and access control.

Encoding / Writing

The majority of tags we sell can be encoded quickly and easily with almost any NFC enabled mobile phone.

Download one the free NFC apps such as NFC Tools or NXP's TagWriter. Then simply enter a URL/link, hold over the NFC product and it's encoded.

Seritag have created step by step guides on writing NFC tags. For iPhone users, read our writing NFC tags with an iPhone tutorial. For Android users, we've written an writing NFC tags with an Android phone tutorial.

If you have a large number of tags to encode, then you might prefer Seritag to encode the tags for you. We can accurately encode hundreds of thousands of tags per day with single, sequential, unique or batched data.

Tags that are being placed in public areas are also best locked. This is a separate memory operation and can also be actioned using the same mobile phone apps.

NFC Chips

Each NFC tag (the physical product) contains an NFC chip. The tiny microchip allows the tag to communicate with the reader and stores the data.

Different NFC chips have different amounts of memory but the amount is always very small - much smaller than a USB stick. Typically, an NFC chip can only store a sentence worth of text or at most, a paragraph. Memory storage is specified in 'bytes' where, roughly, one byte will be one character (such as a letter in a URL/link). The popular NTAG213 chips can store 144 bytes of data.

Some NFC chips can also undertake additional functions. For example, the NTAG213 can also count the number of scans and the NTAG424 or EM|Linq chips offer advanced authentication features.

NFC Tag Management

For most tag use cases, the tags will be encoded/written and placed into location. Any tag in public should also be locked to prevent accidental or unwanted changes to the data. To allow changes to the link/URL after deployment, a tag management system can be used.

A tag management system is a redirect platform where the tags are encoded to link first to the platform and the platform then immediately redirects to the final destination. This may be on based on a set criteria such as time of day, number of scans, etc. This intermediary system allows for future and remote management of tag link destinations.

Tag management systems can also undertake additional functions such as verification in the case of the NTAG424 or EM|Linq authentication tags. In which case, the authenticity of the tag can be checked in real time before a response is provided.

Seritag's powerful and popular Ixkio platform is designed specifically for the management of NFC products and tags. If you are working on a project where tags might require post-deployment changes or are planning on working with authentication tags, then talk to us.