---
title: What are Custom Apps?
slug: using-fusion-signage/HGPi-what-are-custom-apps
docTags: 
createdAt: 2026-08-27T17:51:41.080Z
---

A Custom App is an HTML-based application developed by you that can be played on your screens alongside other content like videos, images, and designs. 

Custom apps run natively on the device and continue to play even without an internet connection.

Custom Apps use the [W3C packaged web application](https://www.w3.org/TR/widgets/#widget-packages) standard. They are simply a zip file with the .wgt extension that contains all the files required to play your custom content, such as HTML files, JavaScript files, CSS files, videos, and images.

[Keep reading on our Developer Portal to learn more.](https://developers.fusionsignage.com.au/docs/custom-apps/introduction/)