Our recommendation
A registration number built for Regulation (EU) 2024/1028
The regulation requires a unique registration number for every unit: issued immediately, free of personal data, and verifiable by platforms and the public. It leaves the format to each Member State. citytax recommends the UPN (Unique Property Number), a fixed 21-character number built on EU standards, which UTEM issues and verifies.
Anatomy of a UPN
- Country
- Two-letter ISO 3166-1 code of the Member State, e.g. IE for Ireland.
- Region
- Three-character NUTS 3 region code from the Eurostat classification, e.g. 061 for Dublin.
- Activity
- Four-digit NACE Rev. 2 activity code, e.g. 5520 for holiday and other short-stay accommodation.
- Unique code
- Nine random characters that make the number unique and impossible to guess.
Example: a holiday apartment in Dublin, Ireland.
Why this design
Fixed length
Always 21 characters in four groups. Easy to read aloud, copy into a listing and validate with a single pattern.
Built on EU standards
ISO country codes, NUTS regions and NACE activity codes: the number itself shows where the unit is and what kind of accommodation it is.
No personal data
Nothing in the number identifies the host or the exact address, as the regulation requires.
Cannot be guessed
The unique part comes from a cryptographically secure random source, not a sequence, so numbers cannot be enumerated or scraped.
No look-alike characters
0/O and 1/I are left out of the unique part, so numbers are not mistyped when copied by hand.
Verifiable by anyone
A free, public, machine-readable check. Platforms run it automatically; guests can check a listing themselves.
How a number is checked
- 1
Shown on the listing
The host receives the number on registration and displays it in every advertisement.
- 2
Checked in the registry
A platform checks it through the API, or a guest on the public website.
- 3
A clear answer
The registry says whether the number is valid, suspended or withdrawn, without revealing personal data.
A public check returns
- Whether the number exists and is valid
- Its status: active, suspended or withdrawn
- The region
- The type of accommodation
Never shown publicly
- The host's name and contact details
- The exact address
- Bookings and guest data
- Income and tax information
Machine-readable by design
One regular expression validates any UPN, so a platform can reject a mistyped number before it even queries the registry.
^[A-Z]{2}-[A-Z0-9]{3}-[0-9]{4}-[2-9A-HJ-NP-Z]{9}$The UPN is citytax's recommendation. Regulation (EU) 2024/1028 leaves the format of registration numbers to each Member State; it requires only that each number is unique, contains no personal data and can be verified.
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