- CPF Generator
- CNPJ Generator
- CNH Generator
- PIS/PASEP Generator
- RENAVAM Generator
- RG Generator
- Chassis Generator
- Certificate Generator
- Credit Card Generator
- Phone Generator
- CNS Generator
- Voter ID Generator
- AIH Generator
- Phone Generator
- Passport Generator
- Person Generator
- Company Generator
- Address Generator
- State Registration Generator
- SSN (USA)
- EIN (USA)
- SIN (Canada)
- CURP (Mexico)
- RFC (Mexico)
- DNI (Argentina)
- CUIT/CUIL (Argentina)
- RUT (Chile)
- CI (Uruguay)
- CC (Colombia)
- DNI (Spain)
- NIE (Spain)
- NINO (UK)
- Codice Fiscale (Italy)
- Steuer-ID (Germany)
- NIR (France)
- NIF Generator
- SSN Validator (USA)
- SIN Validator (Canada)
- CUIT Validator (Argentina)
- RUT Validator (Chile)
- CI Validator (Uruguay)
- DNI Validator (Spain)
- NIE Validator (Spain)
- Codice Fiscale Validator (Italy)
- Steuer-ID Validator (Germany)
- NIR Validator (France)
- NIF Validator
Frequently Asked Questions
We have gathered answers to the most common questions about Help4Dev, its tools, and the responsible use of generated data. If you are a developer, tester, or student, this information will help you use the platform safely and efficiently.
What are Help4Dev tools for?
Help4Dev tools were created exclusively for software development and testing purposes. Generators such as CPF, CNPJ, CNH and others produce mathematically valid numbers — meaning they pass the verification rules of official algorithms — but they do not belong to any real person or company. The goal is to help developers, testers, and students fill in required fields in systems during development and staging phases, without the need to use real data.
Is the generated data real?
No. All data generated by Help4Dev is completely fictional and random. A generated CPF, for example, follows the official Receita Federal algorithm and has correct check digits, but it is not registered in any government database. The same applies to CNPJ, CNH, RG, RENAVAM, and all other documents. Never use this data in real, legal, or commercial situations.
Can I use the generated data outside of development environments?
No. The use of data outside of testing and development environments is strictly prohibited and may constitute a crime. Using fictitious CPF, CNPJ, or other document numbers in real transactions, official registrations, or any context outside software development is considered data forgery and may have serious legal consequences. Help4Dev is not responsible for misuse of the tools.
How does the generator algorithm work?
Each generator implements the official algorithm for the respective document. For example, the CPF generator creates 9 random digits and calculates the 2 check digits using the modulus 11 method, as defined by the Receita Federal. The CNPJ generator follows the same logic with 12 base digits and specific weights. This ensures that the generated numbers are mathematically valid and accepted by systems that perform digit verification.
How does the validator work?
Validators check whether a given number is mathematically correct according to the official algorithm of the document. For CPF, for example, the validator recalculates the check digits from the first 9 digits and compares them with the provided digits. If they match, the CPF is considered valid in terms of format and algorithm. Important: a number that is valid by the algorithm does not mean it is registered in any official database.
Does Help4Dev store the data I generate?
No. Help4Dev does not store, record, or transmit any data generated or validated by users. All processing occurs directly in the user's browser, with no information sent to our servers. Our platform has no user database and does not collect personal information beyond what is necessary for anonymous traffic analysis via Google Analytics.
Why does the validator say a CPF is invalid even though it looks correct?
The validator exclusively checks the mathematical consistency of the check digits. A CPF may look correct visually but have check digits that do not match the expected calculation by the modulus 11 algorithm. Another common cause is entering CPFs with repeated sequences (such as 111.111.111-11), which are rejected by the algorithm even if the digits appear consistent. Also make sure you enter all 11 digits without errors.
Do the tools work for all Brazilian states?
Yes. Most tools generate valid data for any Brazilian state. Some generators, such as Voter ID and AIH, allow you to select the state of origin so the generated number correctly includes the region code. Other documents, such as CPF and CNPJ, have no regional link in their current structure and work universally.
Is the site free?
Yes, all Help4Dev tools are completely free and require no registration. Our goal is to offer useful resources to the software development community at no cost. The site is maintained through non-intrusive advertising via Google AdSense.
How can I get in touch or suggest new tools?
Help4Dev is constantly evolving. If you have suggestions for new tools, found a bug, or want to give feedback, we are open to community contributions. Stay tuned for updates and new features we regularly add to meet the needs of developers.
What is the auto-rotation feature and how do I use it?
Auto-rotation is a feature that automatically generates new data at set intervals, without you having to click the generate button each time. Simply enable rotation and select the desired time interval (for example, every 2, 5, or 10 seconds). This is especially useful for automated tests where you need a continuous stream of fictitious data without manual intervention.
What is the difference between a generator and a validator?
A generator creates fictitious numbers that follow the algorithmic rules of the document (such as CPF, CNPJ, CNH), ensuring the generated data is mathematically valid. A validator, in turn, checks whether a number you provide follows those same rules. While the generator is useful for creating test data, the validator is ideal for checking whether an existing number (or one entered by a user) is correct before processing it in your system.
How can I use generated data in automated tests?
Generated data can be copied directly to your test scripts using the copy button on each tool. For continuous automated testing, you can use the auto-rotation feature to cycle through different values. In frameworks like Cypress, Selenium, or Playwright, simply use the generated values as inputs in your form fields within test cases. The data is mathematically valid and will pass format validation in most systems.
Does Help4Dev work on mobile devices?
Yes, Help4Dev was built with a responsive design and works correctly on smartphones and tablets. The interface automatically adapts to screen size, allowing you to generate and validate data from any device — whether you are in a meeting, in the field, or simply need test data quickly away from your workstation.
Which browsers are compatible with Help4Dev?
Help4Dev is compatible with all modern browsers, including Google Chrome, Mozilla Firefox, Microsoft Edge, Safari, and Opera. To ensure the best experience, we recommend keeping your browser up to date. All algorithm processing runs entirely in the browser (client-side), so no additional installation or plugin is required.
Why is it important to use mathematically valid numbers in tests?
Modern systems implement check-digit validation on document fields before accepting any registration or transaction. If you use random or invalid numbers in your tests, the system will reject the input before you even get to test the main flow you want to validate. With numbers generated by Help4Dev, you can test the correct system behavior — registration, integration, database — with data that passes the validation layer.
Does Help4Dev have a public API?
Currently, Help4Dev does not offer a public API. All tools run directly in the user's browser. However, the generation and validation algorithm logic is implemented in JavaScript/TypeScript and can be inspected in the platform's source code. For larger data volumes or CI/CD pipeline integration, developers typically implement the algorithms locally based on the logic available on the site.
Does Help4Dev generate data for countries other than Brazil?
Yes, Help4Dev offers the NIF (Número de Identificação Fiscal) generator for Portugal, as well as documents such as passport and credit card that follow international standards (ICAO and ISO/IEC 7812, respectively). The main focus of the platform is the Brazilian market, but some international documents are supported. New document types are regularly added based on community demand.
What is LGPD and why does it matter in software development?
The Lei Geral de Proteção de Dados (LGPD — Law 13.709/2018) is the Brazilian legislation that regulates the processing of personal data. For developers, this means that using real CPF, CNPJ, CNH, or other document data in development and staging environments can constitute a LGPD violation, exposing companies to fines of up to 2% of revenue. Using fictitious data generated by Help4Dev is the correct and safe way to avoid legal risks.
How often are the tools updated?
Help4Dev is updated regularly. When there are changes to official document algorithms, such as the new alphanumeric CNPJ format, we update our tools to reflect the new rules. We also continuously add new document types and interface improvements. Keep an eye on the platform's evolution, and if you notice any inconsistency or outdated behavior, let us know — your contribution is essential to maintaining the quality of our tools.