CodeTools

CNPJ generator for tests

Generate fictional, mathematically valid Brazilian CNPJ numbers for development and staging · 100% client-side · no values are sent to the server

These values are fictional Brazilian company registration numbers (CNPJ) and are for tests only. Mathematical validity does not confirm existence, ownership, or registration status.

Quick guide and information

How to use

  1. Choose 1 to 10 values to generate.
  2. Decide whether to show the `00.000.000/0000-00` mask.
  3. Click Generate CNPJ and copy the result into your test environment.

When to use

Use fictional Brazilian CNPJ numbers to fill fixtures, test form masks, validate staging integrations, or simulate companies in environments that must not contain real data.

Never use the result for a real registration, forgery, opening an account, or to bypass an application's controls.

How is a CNPJ validated?

A numeric CNPJ has 14 digits: twelve form the base and the last two are check digits. The calculation uses modulo 11 and different weights in the first and second steps.

The generator calculates the check digits in the browser and rejects sequences made of the same digit, such as `11.111.111/1111-11`.

Practical cases

  • Test a CNPJ mask in a business form that accepts Brazilian documents.
  • Create fixtures for registration flows in QA.
  • Fill API documentation without exposing real data.

Limitations and responsible use

This generator does not query official Brazilian registries, does not verify existence, ownership, or registration status, and does not store the created values.

Use it only in development, QA, and staging. A mathematically valid number does not prove that a company exists.

FAQ

Does the generated CNPJ belong to a company?

The tool does not query registries and does not claim that any result belongs or does not belong to a company. Use the values only in test environments.

Does processing leave the browser?

No. Generation is local and no value is sent to the CodeTools server.

Why is mathematical validity not enough?

Check digits confirm the sequence is consistent, but they do not prove existence, ownership, or regularity with an official source.

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