BBTHEME File

What are BBTHEME files and how to open them

Are you having problems opening a BBTHEME file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BBTHEME files.

What is a BBTHEME file?

A .BBTHEME file is a Blockbench Theme file.

Blockbench Theme files store the visual appearance settings used by the Blockbench editor so that interface colors, fonts, and certain layout styles appear consistently when the theme is loaded. These files define custom look-and-feel options like the interface's base colors (dark, light, borders, buttons, etc.), text styles, and UI fonts. Users create themes via Blockbench's Theme editor (through File → Preferences → Theme), adjust colors and fonts, then export to a theme file. When such a theme file is imported or applied, Blockbench parses the data and re-styles its interface accordingly.

Blockbench writes theme files in a JSON‐based format designed for human readability and manual editing; any text editor can open one. The theme file includes fields for font names (such as the "main font", "headline font", "code font") and for color values tied to UI elements (for example "background", "button", "border", "selected", "wireframe", "text", "checkerboard"). Themes may also include custom CSS rules for further fine‐tuning. Blockbench also allows providing fallback fonts by listing multiple font names separated by commas.

Theme files are authored by Blockbench, versioned alongside the application, and intended to be read by Blockbench to apply style settings on startup or when importing a theme. Editing the JSON directly changes the appearance only when loaded next time. Users may share theme files to provide consistent styling across different installations.

Internally theme files begin with a JSON object that often includes an "id" field near the start and contain recognizable keywords such as HEADLINE_FONT, MAIN_FONT, CODE_FONT alongside color keys like CHECKERBOARD, ACCENT_TEXT, SUBTLE_TEXT, BRIGHT_UI, WIREFRAME, SELECTED, DEFAULT, AUTHOR, BORDER, BUTTON, COLORS, LIGHT, BACK, DARK, GRID, NAME.

How to open BBTHEME files

Important: Different programs may use files with the BBTHEME file extension for different purposes, so unless you are sure which format your BBTHEME file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 23, 2026

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