A PRODUCT OF MTAG.CC

M-Chip.
A tag for things worth keeping.

The M-Chip is a physical NFC tag made for creators. Stick it on a coin, a badge, a print — anything you make. Scanning it links straight to your collectible, so every physical item becomes claimable.

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HOW IT WORKS

Physical item, digital claim

  • 1. CreateMake a collectible — coin, badge, print, whatever you produce.
  • 2. AttachRegister the M-Chip's unique UID to your collectible and write your profile URL on the tag.
  • 3. ClaimWhoever gets the item scans the chip and claims it into their collection.
SETUP

Writing your first chip

  • 1. Enable the Writer APIGo to Collectibles → Writer API and enable it — the key is active for 1 hour, long enough to write a batch.
  • 2. Pick your writer Android browser (WebNFC): Collectibles → Writer API — open in Chrome on Android, pick your collectible, choose with or without Lock-Bit, and tap tags directly to your phone. USB reader (ACR122U & co): write_chip.py — Python script, loops over tags (optional --lock flag). ESP32 + PN532: esp32_writer.ino — standalone writer with its own web UI: on first boot it opens a MTAG-SETUP WiFi portal, you enter WiFi + a one-time setup code, and it pairs itself — includes selectable Lock-Bit. Writer app: scan the QR shown under Writer API — it hands over base, user and key without typing.
  • 3. Write & verifyThe tool reads the tag UID, registers it via GET /api/chip and writes the returned URL as NDEF. Scan the tag with your phone — it should open your collectible.
TAG FORMAT

What goes on the chip

  • NTAG21xThe chips are NTAG213/215/216 — standard NFC tags, ~180–888 bytes usable.
  • NDEF URLThe tag stores your profile claim URL — with UID mirror enabled the reader inserts the physical chip UID automatically.
  • Lock after writingEnable permanent write protection once the URL is on — a locked tag can't be rewritten.

Full reference — endpoints, error codes, QR payload format: API guide · OpenAPI docs

M-Chip is one claim method among several — collectibles also work with photo claims, codes or manual grants. No chip required.

The MakerChip concept was pioneered by Kevin K2 and the makerchip.app community — the M-Chip is our compatible take on it as one of several claim methods.