This is the CNPJ validator, just type the CNPJ and click on validate CNPJ and a message will appear if it is valid or not.
The CNPJ number has three digit segments, the first being the registration number itself, the second (after the slash) the number of branches and the third for the last two values that are the check digits.
Officially, the CNPJ calculation provides for the verification of the eighth digit, but some entities have numbers that, when validated according to this criterion, are considered invalid.
That's why the safest thing is for you to validate the check digits, so that no number will be invalid and your routine is protected in the same way, since the rule is unique and works with any valid CNPJ
Validating check digits
We will show the calculation method in a practical way, for this we will adopt a hypothetical CNPJ number and calculate its check digits: 11.222.333/0001-XX.