> For the complete documentation index, see [llms.txt](https://docs.cnpj.ws/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cnpj.ws/en/blog.md).

# BLOG

- [What is CNPJ](https://docs.cnpj.ws/en/blog/o-que-e-cnpj.md): The National Register of Legal Entities is the registration used by the Federal Revenue to open an institution with or without profit purposes
- [Alphanumeric CNPJ](https://docs.cnpj.ws/en/blog/alphanumeric-cnpj.md): How to calculate the check digits of an alphanumeric CNPJ (Brazilian company registration number)
- [Alphanumeric CNPJ Test Example](https://docs.cnpj.ws/en/blog/alphanumeric-cnpj-test-example.md): The CNPJ.ws API is already prepared. Adapt your application calmly using this example and you'll be ready when the first alphanumeric registrations start being issued, in July 2026.
- [Consult CNPJ with Java](https://docs.cnpj.ws/en/blog/consultar-cnpj-java.md): Learn how to consult company data through the CNPJ using the CNPJ.ws API, with data from Receita Federal, Sintegra, and Suframa using Java.
- [Consult CNPJ for Free with Excel](https://docs.cnpj.ws/en/blog/consultar-cnpj-excel.md): Use this Excel spreadsheet to consult company data through the CNPJ using the CNPJ.ws API, with data from Receita Federal, Sintegra, and Suframa.
- [Consult CNPJ with PHP](https://docs.cnpj.ws/en/blog/consulta-cnpj-php.md): Learn how to consult company data through the CNPJ using the CNPJ.ws API, with data from Receita Federal, Sintegra, and Suframa using PHP.
- [Trigger to Consult CNPJ in Protheus](https://docs.cnpj.ws/en/blog/gatilho-consultar-cnpj.md): Trigger to consult CNPJ in the registration of customers or suppliers in Protheus using ADVPL and the CNPJ.ws API with data from Receita Federal, Sintegra, and Suframa.
- [Keep Customer and Supplier Records Updated](https://docs.cnpj.ws/en/blog/manter-clientes-fornecedores-atualizados.md)
- [Consult CNPJ with Javascript and Node.JS](https://docs.cnpj.ws/en/blog/consultar-cnpj-javascript.md): Learn how to consult company data through the CNPJ using the CNPJ.ws API, with data from Receita Federal, Sintegra, and Suframa using Javascript/Node.js
- [Consult CNPJ with ADVPL (Protheus)](https://docs.cnpj.ws/en/blog/integracao-protheus.md): Consult CNPJ in Protheus using the CNPJ.ws API with ADVPL
- [How to Automate Customer Registration with a CNPJ Lookup API](https://docs.cnpj.ws/en/blog/como-automatizar-o-cadastro-de-clientes-com-uma-api-de-consulta-cnpj.md): Learn how to use a CNPJ lookup API to automate customer registration: accurate official data, no manual typing. With a real-world bitERP example
- [CNPJ.ws Project](https://docs.cnpj.ws/en/blog/cnpjws.md)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.cnpj.ws/en/blog.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.