An Android app for reading and writing Creality RFID filament spool tags. Works alongside CFsync and Spoolman to give you a seamless, end-to-end filament tracking workflow.
Based on the excellent K2-RFID by DnG-Crafts — big thanks for their hard work and open-source contribution.
Creality K1/K2/Hi/CFS printers use MIFARE Classic 1K NFC tags on filament spools to identify filament type, colour, and vendor. CFtag lets you read and write those tags from your Android phone — so you can tag your own spools, re-tag spools with different filament, or link a physical tag directly to a Spoolman spool entry.
When used together with CFsync and Spoolman, the full loop looks like this:
CFtag (phone) ──write──▶ RFID tag on spool
│
└──▶ Creality printer reads tag, knows filament
CFtag ──REST──▶ Spoolman ◀──sync── CFsync
│
└──▶ Usage tracking, remaining weight, history
- CFtag writes filament data + a Spoolman spool ID onto the RFID tag.
- The printer reads the tag and selects the correct filament profile automatically.
- CFsync syncs filament data between your printer and Spoolman.
- Spoolman tracks remaining weight and usage history across all your spools.
| Main screen | Two-tag write flow |
|---|---|
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Many spools ship with two RFID tags. CFtag guides you through writing both in a single flow — no need to re-open the app or re-enter filament details. After writing Tag 1 you are prompted to tap Tag 2 and press Write Tag 2. Both tags end up with identical data including the linked Spoolman spool ID.
- Write & Create Spool — fill in filament details, press the button, and CFtag creates the spool in Spoolman and immediately guides you through writing both tags.
- Link to Existing Spool — pick an existing Spoolman spool from a searchable list (with colour swatch and remaining weight) and write the link onto the tag(s).
- The Spoolman spool ID is stored in the tag's serial number field, creating a stable cross-system identifier between the physical tag, the printer, and Spoolman.
Tap Read (or enable auto-read in settings) to read any Creality-compatible RFID tag and display its full filament information.
Ships with the Creality filament database. You can download an updated database directly from a connected printer over the local network.
- Android phone with NFC
- MIFARE Classic 1K NFC tags (the standard Creality spool tag format)
- Creality K1 / K2 / Hi / CFS series printer
- (Optional) Spoolman instance on your local network
- (Optional) CFsync for printer ↔ Spoolman sync
- Install the APK on your Android device.
- Open the app and tap the menu icon → Settings.
- Enable Spoolman and enter your Spoolman host address and port (default
7912). - Select your Printer model and Brand from the dropdowns.
- You are ready to start tagging spools.
Note: Some Android devices do not support MIFARE Classic tags at the hardware level. If RFID functions are shown as disabled after enabling NFC, your device is not compatible.
- Select Printer, Brand, Type, Size, and Color from the dropdowns.
- Under SPOOLMAN OPTIONS, tap Write & Create Spool.
- Fill in the spool details (vendor, filament name, etc.) and tap Add.
- The spool is created in Spoolman. Tap your first RFID tag to the back of your phone and press Write Tag 1.
- When prompted, tap your second tag and press Write Tag 2.
- Done — both tags are written and linked to the Spoolman spool.
- Select the filament options for this spool.
- Under SPOOLMAN OPTIONS, select the spool from the Spoolman dropdown.
- Tap Link to Existing Spool.
- Follow the Tag 1 / Tag 2 prompts as above.
Tap Read with an NFC tag near the back of your phone (or enable auto-read in settings to have it read automatically on tag discovery).
CFtag is a fork of K2-RFID by DnG-Crafts. The core tag format, encryption, and filament database handling are their work.