If you work in a field where you have to deal with personal data like the NIF, and you can't check to make sure they're valid, this program will really help you out.
With Validador you can confirm that the NIF, NIE, CIF, IBAN bank numbers, and social security numbers that you receive are correct.
Validador was developed with just one menu screen, which has various boxes where you can enter in the corresponding information. Once you've done that, the program will alert you to whether or not the data checks out.
It's a simple, free application that should be ideal for all kinds of businesses.