> ## Documentation Index
> Fetch the complete documentation index at: https://bruno-a6972042-mintlify-059d8a2f.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Request headers

Request headers are **key-value** pairs sent along with an HTTP request to provide additional information to the server about the request. The request headers give the server more information about how to process the incoming request.

**Default Headers**: Default headers are predefined headers that Bruno sends automatically with every request. You do not need to add them yourself, and they are not shown on the Headers tab. To see them on the wire, open the **Timeline** tab after sending a request.

Bruno sends the following default headers:

| Header            | Value                                                                                                                                                                                               |
| ----------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `User-Agent`      | `bruno-runtime/<version>` — the running Bruno app or CLI version.                                                                                                                                   |
| `Accept`          | `application/json, text/plain, */*`                                                                                                                                                                 |
| `Accept-Encoding` | `gzip, compress, deflate, br`                                                                                                                                                                       |
| `Content-Type`    | Set automatically based on the request **Body** type (for example `application/json` for JSON, `application/x-www-form-urlencoded` for Form URL Encoded, `multipart/form-data` for Multipart Form). |
| `Content-Length`  | Set automatically based on the encoded body size.                                                                                                                                                   |
| `Host`            | Derived from the request URL.                                                                                                                                                                       |

You can override any default header by adding a header with the same name on the **Headers** tab.

**Custom Headers**: Custom headers are headers that are **user-defined** and are not part of the official HTTP specification.

## Create request headers in Bruno

1. Create request inside collection.
2. Navigate to the **Headers** tab.
3. Enter the **Name**, **Value**, and an optional **Description** for each header.
4. Save and execute the request.

<img src="https://mintcdn.com/bruno-a6972042-mintlify-059d8a2f/XxWhuIi2kUWmkFRr/images/screenshots/v4/description/header.webp?fit=max&auto=format&n=XxWhuIi2kUWmkFRr&q=85&s=198fc7a6ea7e6bcbc5808bca01e4fda0" alt="req-headers" width="2604" height="1094" data-path="images/screenshots/v4/description/header.webp" />

<Tip>
  To view default headers, navigate to the **Headers** tab in your request. For
  custom headers, check the **Timeline** tab.
</Tip>

## Streaming with Server-Sent Events

To work with Server-Sent Events (SSE), set:

```
Accept: text/event-stream
```

Bruno keeps the connection open, streams chunks into the response panel live, and swaps the Send button for Cancel while the stream is active. See [Server-Sent Events (SSE)](/send-requests/REST/sse) for details on cancellation, collection runs, and CLI behavior.