This service exists to help developers validate EU VAT numbers via a simple REST-based API.
It is a bit of code I wrote about five years ago and haven’t maintained since. It appears to Mostly Work. However since the original API is not stable, your mileage may vary.
Although it was a little experiment, apparently it is being used in a variety of online commerce sites, etc., so I’m open sourcing it in hopes that others will maintain it as I’m focusing all of my time and energy into Codename Prometheus.
Hope this helps.