Test
Check a tag during a project. Is it readable, what does it hold, did the last write work?
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From our studio · Case study
We built the NFC tool we kept reaching for. Then we made it simple enough for anyone.
A free app for Android and iOS that reads, writes and inspects NFC tags, from a link on a sticker to the raw memory of a MIFARE card. Designed and built in-house by Xerxes.

01Overview
The app reads and writes NFC tags, digs into their raw memory when you need it, and keeps a history of everything you've scanned. It all starts from one dashboard, where each task has its own clearly labelled tile.
NFC is the point of the app. It also scans and creates QR codes, because people who work with tags usually work with codes too, but that's a side door, not the front one.
02Why we built it
NFC kept coming up in our client work, and so did the same three jobs. Instead of switching between tools for each one, we built a single app that does all three properly.
Check a tag during a project. Is it readable, what does it hold, did the last write work?
Put a link, text, contact card or Wi-Fi details on a tag, quickly and reliably.
Pick up an unknown tag and see exactly what it is and what is stored on it.
03The principle
Every action should be easy to recognise, and every result should be clear before you act on it.
04Goals
Each card links to the chapter that shows how the app meets it.
A first-time user picks Scan Tag or Write Tag without help.
See chapter 11 → 02A tag may hold a link, a contact or raw data. You see which, in plain view.
See chapter 08 → 03Clear input, a clear status, and nothing permanent without a warning.
See chapter 09 → 04Every scan and write is kept in Tag History, filtered the way you need.
See chapter 11 →05Approach
How might the app help people find the right NFC action quickly, understand the result, and write to a tag with confidence?The design question
Three kinds of people pick up an NFC app, and the same screen has to work for all of them.
They tap a tag and want to know what it is.
Links on product stickers, contact cards, Wi-Fi details for guests.
Developers, installers and testers who need the raw memory. People like us.
What the research says
The time it takes to choose grows with the number of options in front of you.1
NFC tools and QR tools sit in two short rows, not one long list.Moving advanced features to a secondary screen makes an app easier to learn and less error-prone.2
Expert tools live behind a single Advanced tile.People need timely feedback on what the system is doing, and protection from mistakes they can't undo.3
Status before every write, and a warning before anything permanent.06What it reads
Most NFC apps stop at the standard format. Ours goes down to the chip, because that's where testing and inspecting actually happen.
Android and iPhone aren't equal here. Android gives apps deeper access to NFC hardware. Everyday reading and writing works on both, but some low-level tools are Android-only, and the app says so on screen instead of failing silently.
07How it evolved
We already knew the problem from the inside. That made the scope easy to set, and the hard decision easy to spot.
NFC kept coming up in client projects. We were checking, writing and inspecting tags with whatever tools were to hand, so we built the one we wanted.
Memory dumps and raw block writes are expert territory, and they can do damage. We kept them, but one tap further in, behind a single Advanced tile, with permanent actions clearly marked.2
React Native gives one codebase for Android and iOS. Sign in with Google and your tag history is saved to the cloud with Firebase, so it follows you to a new phone. Or carry on as a guest.
Under a month from first screen to launch, on the App Store and Google Play.
Tap Scan Tag and hold the phone to a tag. Everything the app learns is laid out in plain view, and nothing happens until you choose.
“Tag read”, with one button to scan the next one.
Its unique ID, the technologies it speaks, its capacity and whether it can be written.
Each NDEF record with its type, so you know a link is a link before you go near it. A blank tag says so, and points to the Advanced tools.
Save the read to the cloud, or share the full dump with a colleague.
Text, a link, Wi-Fi details, a contact card, or a custom record.
One field per kind of record, with a live status underneath. You see “ready to write” before you touch the tag.
Write to tag stays disabled until there's something to write, so you can't send an empty record by accident.
Housekeeping sits below the main action. Lock is in red, because it can't be undone.
Locking is permanent, so the app asks first. A locked tag can never be written again, so the action is marked in red and confirmed before it runs.3
10Advanced
This was the hardest call in the project. Raw memory tools are what made the app useful to us, and they're exactly what can confuse or harm a tag in the wrong hands. So they're all here, but in one place, with plain explanations and no surprises.
Reads each sector using the common factory keys. Sectors protected by a custom key are reported as locked rather than breaking the dump. You can also write a single 16-byte block.
A closer look at the chips found in most stickers and cards.
Send raw commands to smart cards and read the responses.
The app explains what each tool does before you run it.
The home screen is where the “anyone can use it” promise is kept. Six tiles, two rows, every one labelled twice.
Write & Share leads, with more behind the carousel dots.
Scan Tag, Write Tag, Advanced: basic to expert, left to right.
Scan QR, Create QR and Tag History.
Your last scans, one tap from the full result. When it's empty, it tells you which tile to tap first.
Home, Scan, Write and Settings, with the active tab in orange.
Answers goal 4 · Tag History
Scans and writes are kept together, with filters for each and the key facts on every row: UID, chip type, whether it held NDEF data, and when. Signed in, the history follows you to a new phone.
12Also does QR
Scan a code with the camera, or create your own from text, a link, Wi-Fi details or a phone number, then save or share it. Same app, same simple layout.
13Why it makes sense
Two short, grouped rows beat one long list.1 That's the dashboard.
Beginners never trip over them; experts are one tap away.2 That's the Advanced tile.
Show what a tag holds, show the status before a write, and warn before anything permanent.3 That's the read, write and lock flows.
Simple jobs up front, expert tools one tap in, and no surprises. That's why it works for a first-time user, and for us.
14What we measure
The app has only just launched, so there are no results to report yet, and we won't invent any. These are the signals we track from day one.
Tracking since launch · October 2026Can a new user read a tag without help?
Do writes finish, and on which chips do they fail?
Do people succeed on the second try?
How many people go beyond scan and write?
Do people come back to past tags?
Is the build solid across devices and NFC chipsets?
Next: testing permission, empty and unreadable-tag states on a wider range of real devices and chips.
15Try it
NFC & QR Utility is free on Android and iOS. If your product needs NFC, whether that's tags, cards or a custom app, the team that built this one can help.
Sources
Research is cited to explain design decisions, not as proof of this app's results. App screens show sample data.
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