Hex

Because while you may be valid, your theme is questionable.

Hex is a Visual Studio Code extension that validates colour theme files against the official VS Code workbench colour schema. It catches format errors, flags deprecated properties, and shows how much of the available colour palette your theme actually covers.

Features

Schema-Aware Validation

Hex loads the workbench colour schema directly from your running VS Code instance and checks each colour property in your theme file for:

• Format correctness -- hex colours must be #RGB, #RGBA, #RRGGBB, #RRGGBBAA, or the literal default
• Transparency requirements -- some properties require an alpha channel (8-digit hex) to avoid obscuring editor content
• Deprecated properties -- properties marked for removal in the schema are flagged as warnings
• Unknown properties -- anything not in the schema is flagged as invalid

Live Revalidation

Hex watches the validated file for changes and revalidates automatically. Edit your theme, and the results refresh without needing to re-run anything.

Filtering and Search

The built-in filter bar supports:

• Text search by property name
• Match Case toggle
• Regular Expression toggle
• Errors only filter (may be paired with warnings)
• Warnings only filter (may be paired with errors)

Error and warning counts are always visible in the filter bar.

Click-to-Navigate

Click any validation result to jump directly to that property in the editor. Hex finds the property definition, highlights it, and brings the editor into focus.

Coverage Statistics

Hex shows how many colour properties your theme defines relative to the full set of available workbench colours, giving you a quick sense of how comprehensive your theme is.

Usage

Commands

Command	Description
Hex: Show Hex	Open the Hex panel
Validate selected theme file in Hex	Validate the currently selected .json file
Open and validate theme file in Hex	Open a file picker to choose a theme file

Accessing Commands

• Command Palette -- search for "Hex"
• Editor toolbar -- the validate icon appears in the title bar when a .json file is open
• Explorer context menu -- right-click any .json file in the file explorer

Theme File Format

Hex expects a JSON file with a top-level colors object:

{
  "colors": {
    "editor.background": "#1e1e1e",
    "editor.foreground": "#d4d4d4",
    "activityBar.background": "#333333"
  }
}

License

hex-theme-validator is released under the 0BSD.

This package includes or depends on third-party components under their own licenses:

Dependency	License
@gesslar/toolkit	0BSD
@vscode/codicons	CC-BY-4.0
json5	MIT
yaml	ISC