How to Apply JSON Theme in Power BI

Tired of the default blue and yellow in your Power BI reports? Using a custom theme is the best way to apply consistent branding, save time, and make your reports look incredibly professional. This guide will show you exactly how to apply a JSON theme in Power BI, walking you through what themes are, where to get them, and the step-by-step process to transform your visuals.

What is a Power BI Theme and Why Use One?

A Power BI theme is a simple file that tells Power BI how your reports should look by default. Instead of manually changing the colors, fonts, and sizes of every chart, you apply a theme, and all new visuals automatically adopt that style. This file is written in a format called JSON (JavaScript Object Notation), which is just a structured text file that defines properties like colors, font sizes, visual backgrounds, and more.

Using a custom theme is a game-changer for a few key reasons:

Brand Consistency: Ensure every report your team produces uses official company colors, fonts, and logos. This creates a cohesive and professional experience for anyone viewing your data.
Efficiency and Speed: Stop wasting time in the formatting pane. Applying a theme takes seconds and standardizes dozens of settings at once, letting you focus on the insights, not the design tweaks.
Scalability: When everyone on your team uses the same theme file, you guarantee that all reports, regardless of who built them, share a unified look and feel.

Think of it as a style guide for your data. You set the rules once in the JSON file, and Power BI handles the rest.

Getting Your JSON Theme File Ready

Before you can apply a theme, you need a theme file (with a .json extension). You have three main options for getting one, ranging from easy to highly customized.

Option 1: Download a Pre-Made Theme

The easiest way to get started is to use a theme someone else has already built. The Power BI community is generous, and there are many places to find high-quality, pre-made themes you can download and use for free.

The Power BI Community Theme Gallery: The official community site has a dedicated gallery where users submit themes. You can browse different styles and download the ones you like.
GitHub Repositories: A quick search on GitHub for "Power BI themes" will reveal countless repositories where developers and analysts share their JSON files.
Blogs and Resource Sites: Many Power BI experts and agencies share theme files on their websites. This is often a great source for modern and visually appealing designs.

This approach is perfect if you need a clean, professional look quickly and aren't tied to a specific brand palette.

Option 2: Use an Online Theme Generator

If you need to use specific brand colors but don't want to write code, a theme generator is your best friend. These web-based tools provide a user-friendly interface to pick your colors and settings, then generate the JSON file for you.

A popular choice is the PowerBI.tips Theme Generator. You can simply paste in your hex codes, select fonts, and adjust a few settings. When you're done, you click "Download" and get a perfectly formatted JSON file.

This is the ideal middle ground for most users - it offers full customization without requiring you to touch a single line of code.

Option 3: Manually Create or Edit a JSON File

For complete control, you can create or edit a JSON theme file yourself using a simple text editor like VS Code or even Notepad. While it might seem intimidating, the basic structure is quite straightforward.

A very simple theme file looks something like this:

Breaking Down the JSON Structure

name: The name of your theme that appears inside Power BI.
dataColors: This is the most important part. It's a list of hex color codes that Power BI will use in order for charts and graphs. The first color in the list will be used for the first data series, the second for the second, and so on.
background: The default color for report pages and visual backgrounds.
foreground: The color used for text like labels, axes, and titles.
tableAccent: The color used for grids and accents in tables and matrices.

You can go much deeper by adding a visualStyles property to customize every element of every visual type (e.g., set the bar chart title font to 14pt Arial Bold). However, starting with the five properties above is enough to make a massive impact on your report's appearance.

Pro Tip: When editing JSON files, a single missing comma or bracket can cause an error. Use a text editor with JSON validation (like VS Code) to automatically highlight any syntax mistakes.

How to Apply a JSON Theme in Power BI Desktop

Once you have your .json file saved on your computer, applying it takes less than a minute. Follow these simple steps.

Open your report in Power BI Desktop.
Navigate to the "View" tab in the main ribbon at the top of the window.
In the "Themes" section, you'll see a gallery of default themes. Click the small dropdown arrow on the far right of the gallery.
A menu will appear. At the bottom, click on "Browse for themes."
An "Open" file dialog box will pop up. Navigate to where you saved your .json theme file, select it, and click "Open."

That's it! Your report will immediately update to reflect the new theme. You'll see a notification that says, "Theme imported successfully." All of your visuals will instantly switch to the new data colors, backgrounds, and fonts you defined.

What Changes and What Doesn't?

Your new theme only applies default formatting. If you have previously gone into the formatting pane for a specific visual and manually changed a color or font, that manual override will remain. The theme file won't touch it.

To have the theme apply to a visual you previously customized, simply find the "Reset to default" button at the bottom of the formatting pane for that visual. This will undo your manual changes and allow the theme's styles to take over.

Common Issues and Best Practices

Using themes is powerful, but a few best practices can help you avoid common headaches.

Having a Central Theme File: Save your company's official theme file in a shared location where the entire team can access it, like a SharePoint site or a shared network drive. This prevents people from using outdated or incorrect versions.
Keep Accessibility in Mind: When choosing your dataColors, make sure there is enough contrast for them to be easily distinguished. Use an online contrast checker to test your color palette and ensure your reports are readable for everyone.
"My Theme Won't Import!": The number one reason a theme fails to import is a syntax error in the JSON file. A misplaced comma, a missing bracket, or an extra quote can stop it from working. Run your file through a JSON validator online to quickly find and fix the error.
Apply the Theme First: When starting a new report, get in the habit of applying your custom theme before you start building visuals. This saves you from having to go back and reset any manual formatting later on.

Final Thoughts

Applying a JSON theme is a straightforward and highly effective way to create polished, branded, and consistent Power BI reports. By defining your styles once, you simplify your workflow, speed up report development, and ensure a professional output every single time. It's a foundational skill for any serious Power BI developer.

Perfecting themes tackles the visual side of reporting, but the real time-sink is often the data analysis itself. Many teams are still manually pulling data from different platforms and wrestling with complex tools just to get answers. At Graphed, we've built a tool to eliminate that friction by letting you connect your sources and create entire real-time dashboards using simple, natural language. Our approach turns hours of dashboard configuration into a short conversation, so you can move straight to getting the insights you need to grow your business.