OpenTag3D.info supports reading and writing over WebNFC, which is compatible with Android only.

Open OpenTag3D.info

This guide only applies to brand-new, blank, unprotected NTAG215 and NTAG216 tags. The default MFU export uses NTAG215 metadata and can be written to NTAG215 or NTAG216. The optional NTAG216 export uses that tag type’s larger advertised capacity.

1. Download MFU (.bin) from Step 2 and place the file in your ProxMark3 client working directory.
2. Connect the ProxMark3, start its client, place the target tag on the antenna, and identify it: hf mfu info
3. Restore the MFU dump to the tag's writable user-memory pages: hf mfu restore -f <downloaded-file>.bin
4. Read the resulting NDEF record to verify the OpenTag3D payload: hf mfu ndefread You can also read the full tag without creating another file: hf mfu dump --ns

Do not add -s, -e, or -r for a normal NTAG. Those options are for special or magic tags and attempt to write UID, version, signature, password, or configuration data. The normal restore command skips the factory UID and protected configuration pages.

See the official Proxmark3 client documentation for hf mfu restore and the MIFARE Ultralight command list.

Proxmark3 Easy image from edvoncken.net.

NFC Tools is a free, basic NFC reader/writer available for Windows, macOS, and Linux. It supports many USB-connected NFC readers and writers. We recommend the ACR122U, which typically costs about $30 and is available from many online retailers.

This process has been tested with NFC Tools 18 and a USB-connected NFC writer.

1. In Step 2 above, open Download As and download the JSON (.json) file.
2. Open NFC Tools and select the Write tab.
3. Select More → Open, then choose the downloaded JSON file.
4. Place the NFC tag on the connected writer and click Write.

Verify the written payload:

1. Open the Information tab in NFC Tools.
2. Click the ... button next to Record 1.
3. Copy the hexadecimal payload shown there and paste it into the OpenTag3D website to verify that the payload was written correctly.

Sony RC-S370 image by Project Kei via Wikimedia Commons, CC BY-SA 4.0.

Flipper Zero can write compatible NFC tags, but we do not have a tested guide yet. If you have successfully written OpenTag3D data with one, share it with the OpenTag3D community at discord.opentag3d.com.

NDEF is a standard container for records stored on NFC tags. It lets compatible readers identify the record type and pass its bytes to the correct application.

Record type

MIME

MIME type


Warning: Undefined variable $payloadSpec in /var/www/html/filament/opentag3d.php on line 965
application/opentag3d

Payload

The raw bytes represented by the hexadecimal payload in Step 2, without the displayed whitespace.