Spool tag formats compared
Six NFC/RFID formats are used on filament spools today. This page puts them side by side, on 6 November 2026, with every figure taken from the format’s own specification or, for Bambu Lab and Creality (no official specification), from public reverse-engineering work. It describes; it does not rank. OpenSpool and OpenTag3D have their own pages.
| TigerTag | OpenPrintTag | OpenTag3D | OpenSpool | Bambu Lab (reverse-engineered) | Creality CFS (reverse-engineered) | |
|---|---|---|---|---|---|---|
| Chip | NTAG213 / NTAG215 | NFC-V, ICODE SLIX2 (320 B) | NTAG215 / NTAG216 | NTAG215 / NTAG216 | MIFARE Classic 1K | MIFARE Classic 1K |
| Bytes for one full record | 80 (+ 64 B signature) | 176 (248 B on the tag) | 224 | 126 (JSON) | not documented (1 KB chip) | 48 |
| Colours, max | 3 | 6 | 4 | 1 | 2 | 1 |
| Nozzle and bed min / max | yes | yes | yes | nozzle only | nozzle; one bed value | no |
| Drying temperature and time | yes | yes | yes | no | yes | no |
| Remaining quantity on the chip | yes | yes | no | no | no | no |
| HueForge TD | yes | yes | yes | no | no | no |
| Free text message | 28 B | no | no | no | no | no |
| Signature verifiable offline | ECDSA-P256, public key published | no | no | no | RSA-2048, public key not published | no |
| Chip rewritable | yes | yes | yes | yes | no (rejected once modified) | no |
| Open offline product catalogue | 20,348 products | 15,874 packages | no | no | no | no |
| Chip corrections after the factory | one open, standardised API for every brand; the SDKs diff and patch the chip, signature kept valid | no | optional data_url to an API each maker builds and hosts itself; no common format, SDK or update workflow |
no | no | no |
What the table shows
Section titled “What the table shows”- The most compact complete record. TigerTag stores a full print record — temperatures, drying, quantities, colours, TD — in 80 bytes, against 176 for OpenPrintTag and 224 for OpenTag3D. The two smaller records carry less: Creality’s 48 bytes hold no temperature, OpenSpool’s 126 bytes hold seven fields. It is also the only format here that fits an NTAG213, signature included.
- Complete offline, thanks to the catalogue. A TigerTag+ product id resolves against the bundled public catalogue — 20,348 products with name, series, SKU, barcode, photo and refill flag — with no network and no account.
- Predictable updates. A brand corrects a product once, on the API every brand shares; any reader then patches the chips already sold.
- Not the most fields on the chip. OpenPrintTag carries more colours and fields TigerTag does not (GTIN, length). What sets TigerTag apart is the combination: a complete record in few bytes, an offline-verifiable signature and an open catalogue of 20,000+ products, on an NTAG213.
Sources
Section titled “Sources”- OpenPrintTag: field list, size from the reference test vector
01_info.yaml, catalogue count from the openprinttag-database README. - OpenTag3D: specification and its memory map.
- OpenSpool: tag format, size from its documented example.
- Bambu Lab: RFID Tag Guide (Bambu Research Group, reverse engineering).
- Creality CFS: K2-RFID (reverse engineering).
- TigerTag: the specification.
A figure is wrong or out of date? Open an issue: this page is corrected, not defended.
Related: Compatibility, TigerTag+ Certified