utility

NFC Tap Log

Open a routine or maintenance log from an NFC tag or QR code, check the last action, and record work locally.

Local processing

About your filesFiles and content selected in this tool are processed in your browser and are not uploaded to a Browser Kitty backend.

Operation demo See the basic workflow in a short video.

About this tool

NFC Tap Log makes an NFC tag or QR code on an object a shortcut to that object's routine work history. Use it for air-conditioner filters, water filters, cleaning areas, and similar items. Check when cleaning, replacement, or inspection last happened and how many days have passed, then add a new record after completing the task. Simply opening a tag never marks the job as done.

Each item has a name and action label, an optional suggested interval, a browser-local memo, and a history of completed actions. On supported Android browsers over HTTPS, you can write the item's URL to an NFC tag and verify it by reading it back. QR codes and the Home list work without Web NFC. History stays within each browser/device, with no automatic cross-device sync.

Good for

Check the previous cleaning date from a tag on an air-conditioner or air-purifier filter
Track replacement dates for water filters and other consumables attached to specific objects
Record completed cleaning and routine inspections, and review elapsed time or past entries
Print QR labels that open the same item page on devices without in-page Web NFC

What it can do

Key capabilities available in this tool.

Open an object's log from an NFC tag or QR code attached to the object
See the previous action date, days elapsed, entry count, and optional suggested interval
Record work only after pressing the action button, with dates and optional notes
Write the item's URL to an NFC tag and read it back for verification on supported Android browsers over HTTPS
Save a QR PNG or print a label with the same URL; search, edit, and undo entries without NFC
Export history CSV, back up and restore items and events with JSON validation, in Japanese or English

How to use

Choose New tag, then enter the object's name and the action to record, such as Cleaned or Replaced.
Optionally set a suggested interval and a memo that stays on this device, then create the item.
On a compatible Android browser using the HTTPS app, choose Write to NFC tag, review the overwrite warning, and hold the phone near the tag.
Optionally use Read back & verify to compare the item ID, name, action, and interval. Without NFC, save a QR PNG or print a QR label.
Next time, open the item using the NFC tag, QR code, or Home list, then check the previous date and days elapsed.
Only after actually completing the work, press the record button. Opening a tag or QR code alone creates no record.
Export history as CSV when needed and keep a complete JSON backup in case you change devices or clear browser data.

Supported

NFC: Write, read, and verify a tag URL via Web NFC / NDEFReader in compatible Android browsers on a secure, top-level HTTPS page.
QR: Generate the same item URL as a QR code and export it as PNG or print a label.
History: Last action date, elapsed days, count, optional interval, search, sorting, memos, history editing, and Undo.
Storage: Items and events are saved to IndexedDB in this browser; export CSV or a complete JSON backup and restore.
Environment: Desktop/mobile and Japanese/English. The main logging features also work without Web NFC and from a saved standalone HTML file.

Limitations and notes

In-page NFC reading and writing requires compatible Android browsers over HTTPS. iPhone Safari does not provide the Web NFC API used here, although a prepared NFC URL tag or QR can open the item page.
Direct Web NFC is unavailable from a saved file:// HTML page; use the hosted HTTPS version for NFC operations.
History and local notes are separate for each browser/device and do not sync automatically. Opening a tag on another device does not automatically transfer past records.
Tag URLs contain the current app site's URL, so tags made on GitHub Pages and Browser Kitty point to different origins. Portable names and action labels are not secret; never store passwords or sensitive data in them.
Writing an NFC tag overwrites its existing NDEF contents. Small tags may not fit long names or action labels.
There is no cloud backup, scheduled notification, or tamper-resistant audit log. Save a JSON backup before clearing browser site data.

Frequently asked questions

Can I use NFC tags on an iPhone?

iPhone Safari cannot write or scan tags through this app's Web NFC API. You can open a previously prepared NFC URL tag or use a QR code, then press the button to log completed work.

Does tapping a tag automatically log an action?

No. The NFC tag or QR code only opens the item screen. A new history event is added only when you press the record button after doing the task.

Will the history move to a new phone?

Not automatically. History is stored per browser. Export a JSON backup and restore it on the new device; CSV is for review, not restoration.

What happens if an NFC tag already contains data?

Confirming a write replaces the existing NDEF content. Do not overwrite a tag that contains information you need to keep.

Are cleaning or inspection records uploaded to a server?

No. Item data, browser-local notes, history, QR generation, and backup processing run locally; the app does not upload records to a server.

Offline version and source code

nfc-tap-log.html is a standalone file containing the logging UI, QR generation, search, and CSV/JSON exports. Its core features work when opened locally, but direct Web NFC read/write does not work from file://. Use the hosted HTTPS app in a supported Android browser for NFC tag writing and verification.

View source on GitHub