# GSTR-3B: Introduction

This section introduces the JSON-based APIs provided by Octa for automating workflows with **GSTR-3B data**. These APIs
allow you to fetch filed GSTR-3B data from the Government portal, export it, and download the resulting Excel file,
enabling faster and more reliable compliance workflows.

## Company Header

All GSTR-3B APIs require the following HTTP header to identify the company you want to work on.

```
Octa-Company: <Company-ID>
```

`Company-ID` must be specified exactly as displayed in Octa (e.g. `oc-xxx`).

## How to find Company ID?

You can use the following steps to find your company ID:

- Login to [Octa GST](https://cloud.octagst.com)
- On the home page, find the company you want to use for APIs
- Click on the **Information** button, this will display company information
- Check the **Company ID**