All Things IoT | Losant Blog

Platform Update - Private Application Files and Custom HTML Block Code Generation

Written by Dylan Schuster | Tue, Oct 28, 2025

Today’s update adds a long-requested feature for storing private static resources within your Losant application. We're also continuing to expand on our AI-assisted application development features. 

Private Application Files

Losant's Application Files has long allowed for storing static resources used within IoT applications: device images, experience script files and stylesheets, and notebook execution outputs. The shortcoming of this feature has always been that the files are served through public URLs – meaning Application Files were not well-suited for storing sensitive data or device firmware images.

Today's release solves for those use cases by providing private file storage within your applications. Private files can be added to your application through several methods:

Once added, private Application Files can only be accessed through a signed URL that is only valid for a time period defined by you. There are several ways to generate these URLs for end user consumption:

We're thrilled to bring this much-requested feature to our users as it improves both the security and usability of our IoT platform. The introduction of private files means it's no longer necessary to separately manage sensitive or end-user-specific resources in a third-party storage provider like Amazon S3.

Custom HTML Block Code Generation

Today's release also exposes a new code generation service for helping users write custom HTML, CSS, and JavaScript for use within Losant dashboards. Given a detailed prompt and a set of data queries, this service creates dynamic custom visualizations that can even make use of third-party APIs and graphing libraries.

Losant's Custom HTML Block has long been an escape hatch for developing custom visualizations within our drag-and-drop dashboard builder that are not otherwise supported by our native blocks. By allowing builders to define the application data they would like to expose and to bring in open-source libraries through CDNs, they can create virtually any kind of interactive graph. However, it requires advanced web development skills to bring such a block to life, and many of our application engineers have expertise in other areas of the IoT product stack.

The block's new code generation service takes away most of the work in developing these visualizations. While some prompt responses may require a bit of tweaking to get exactly what you're looking for, the results speak for themselves.

The block above was created using the following prompt:

`queries['time-series-0']` depicts hourly temperatures, in Fahrenheit, over the last 7 days. Please create a chart that depicts this data as a heatmap, the cells of which have a background color corresponding to a standard hot vs. cold color temperature scale. The actual temperature should be displayed in a tooltip on hover of each cell.

The service can even pull in third-party graphing libraries (though some, like Google Maps, may require the manual addition of API keys).

This block is a fully interactive, three-dimensional chart powered by Plotly, and it was created by configuring three time series query segments within a Custom HTML Block and by providing the following prompt:

Plot the relationship between x (time-series-0), y (time-series-1), and z (time-series-2) in a 3D, interactive chart.

When we added Function Node code generation a few months ago, and followed that up with our AI-powered documentation agent, we knew that these were just the first steps in bringing the power of artificial intelligence and generated content to our IoT application developers. There are several other opportunities within our platform for reducing workload and time to market for our users, and we will continue rolling these features out in the coming months.

Other Updates

As always, this release comes with other features and improvements, including:

What’s Next?

With every new release, we listen to your feedback. By combining your suggestions with our roadmap, we can continue to improve the platform while maintaining its ease of use. Let us know what you think in the Losant Forums.