---
source: https://qlik.dev/extend/create-with-extension-api/qext-file-overview/
last_updated: 2025-07-03T16:05:11+02:00
---

# Work with the meta data

The extension metadata file (QEXT) is a JSON file, and is used by Qlik Sense to
identify the visualization extension. It contains the metadata used for the
library or assets panel. When deployed to Qlik Sense, the visualization
extension is displayed in the Charts section of the assets panel or library panel.

> **Tip:** Make sure your file meets the requirements of a valid JSON file when
> creating your QEXT file.

JSON validator: [JSONLint](http://jsonlint.com/)

All visualizations must contain at least one QEXT file and one JavaScript file.

> **Notes:**
>
> - The QEXT file extension must be in lower case letters, as in `HelloWorld.qext`.
> - The JavaScript file and the QEXT file must have the same name,
>   including matching case. The name must also be unique in the Qlik Sense system
>   so prefixing of the name should be considered. For example, `com-qliktech-helloworld`.

## Properties

### Structure

The following properties can be defined in the QEXT file.

`name`

The `name` property is mandatory.

This is the name of the visualization extension and is displayed in the
library as well as in the preview.

> **Note:** It is recommended to use a unique name for the visualization to avoid interference with other visualizations that may
> have the same name.

`type`

The `type` property is mandatory.

This defines the type of extension. It should always be visualization for
visualization extensions.

`description`

This defines the description visible in the preview of the visualization extension.

`icon`

Default is `extension`.

This defines the icon displayed in the library. It can be:

Library icons

| Syntax                 | Icon               |
| ---------------------- | ------------------ |
| `"bar-chart-vertical"` | icbarchart.svg     |
| `"extension"`          | icpuzzle.svg       |
| `"filterpane"`         | icfilterpane.svg   |
| `"gauge-chart"`        | icgaugechart.svg   |
| `"line-chart"`         | iclinechart.svg    |
| `"list"`               | icfield.svg        |
| `"map"`                | icmap.svg          |
| `"pie-chart"`          | icpiechart.svg     |
| `"scatter-chart"`      | icscatterchart.svg |
| `"table"`              | ictable.svg        |
| `"text-image"`         | ictext.svg         |
| `"treemap"`            | ictreemap.svg      |

`preview`

> **Note:** If `preview` is undefined, the `icon` definition will be used.

This defines which preview image is to be used. The preview image is displayed
in a pop-up when you select the visualization extension in the library.

You can define a custom preview image file. For an example of how this is
defined, see the HelloWorld code example.

> **Note:** The preview image should be saved in PNG format.

Syntax:

`"icon": "<CustomImage>.png"`

`version`

This defines your individual version handling of the visualization extension.
This setting is manually defined. Semantic versioning is recommended.

`author`

This defines the author of the visualization extension. This setting is
manually defined.

## Examples

Example: Hello world QEXT file

```javascript
{
    "name": "Hello World",
    "description": "Hello world example",
    "preview": "helloworld.png",
    "type": "visualization",
    "version": 1,
    "author": "Qlik International"
}
```

[image: select custom theme]