Yes, if you are saying that it is not performing a lookup, that is correct. It validates tax ID numbers according to the rules available in each country. Some countries use a checksum, others don't. Some countries have components like birth date encoded into the number, others don't.
If for example, you were going to perform a lookup, you might want to use Tax ID Pro on the front-end of the form to validate the number before sending it to a slower and more expensive lookup service.
Tax ID Pro is an API that helps you validate tax ID numbers. I've worked on this off and on for a couple years now. I just launched a complete overhaul, re-writing the entire front-end with Next.js and back-end with FastAPI. My next project is to create an SDK for various languages to make implementation even easier.