What the check looks for
A UETR uses five groups of hexadecimal characters in an 8–4–4–4–12 arrangement. The third group starts with 4, indicating UUID version 4. The fourth starts with 8, 9, a or b, indicating the variant.
The tool trims whitespace at the ends for analysis and accepts uppercase letters. It does not silently add missing hyphens, replace characters or create a new reference.
A pass answers one narrow question
It means the text has the expected structure. Anyone can generate a UUID, so a pass cannot establish that the reference belongs to a real transfer, was issued by a bank or has reached its beneficiary.
For a format-valid reference that produces no match, read why a UETR can show no result. For the background, see what a UETR number is.
Your input stays in the tool
This format check runs in your browser. Typing here does not send the reference to a bank or to the transaction lookup endpoint. Opening a lookup and submitting its separate form is a different action.