VIES Uptime, Measured — 28 Member States, One Sample Every 15 Minutes

The European Commission tracks the availability of each member state's VAT validation backend through an endpoint that checks if it is reachable at any given moment. This data is collected every 15 minutes, resulting in a sample for each state. Over a five-day period, totaling 548 samples per state (15,344 samples overall), the findings reveal that 15 out of the 28 member states experienced no downtime, while the remaining 13 faced some level of unavailability.

The aggregate availability across all member states and samples is 98.71%, which, while accurate, is considered meaningless by the author. This is because individual member states, such as Germany, Ireland, and Latvia, exhibit vastly different patterns of availability and unavailability, and these variations are far more significant than a single aggregate figure.

The breakdown by country shows that Germany, in particular, has a unique pattern. It is available in every sample from 01:00 to 20:00 UTC but unavailable during the 22:00 to 00:59 UTC window. This behavior repeats daily, with the 21:00 hour marking the approximate boundary of unavailability. The remaining 15 states with no downtime represent an exception to the general trend, demonstrating that the reliability of VIES varies significantly among member states.