Brazilian CPF Generator for Software Testing

How the generator works and when to use it

This generator creates fictional CPFs using the mathematical check-digit rule. In valid mode, the number passes common system validations; in invalid or mixed mode, it helps test rejections, error messages, masks and API handling.

A mathematically valid CPF is not the same as a real CPF. The generated numbers do not belong to real people and no government databases are queried. The goal is only to validate flows and business rules that require CPF formatting.

Validation algorithm summary (in plain language)

A CPF has 11 digits. The last two are “check digits” calculated from the first nine using weighted multiplications and successive sums. If the computed check digits don’t match, the number is invalid.

Obvious sequences such as 000.000.000-00, 111.111.111-11, etc. are never accepted. Our generator automatically avoids these cases.

Best practices when using fictitious CPFs

• Use generated CPFs only in test, development, or demo environments.
• In the back end, store the value without punctuation; apply the mask only for display.
• Do not log test CPFs in production logs/analytics.
• For validation tests, combine with fictitious name and address fields.

Tools that go well with this generator

For a complete testing flow, also use:

• • CPF Validator to check input rules.
• • Name Generator to fill forms.
• • Address Generator for realistic simulations.

Limitations and privacy

This generator does not check tax status with the Federal Revenue Service and does not link to personal data. It is intended for testing, and generated values should not be mixed with real databases. For official uses, consult government channels.