Dart SDK

A prebuilt Dart SDK is available for IDE consumption at: third_party/dart/tools/sdks/dart-sdk/.

Visual Studio Code

  1. Download and install Visual Studio Code

  2. [optional] Setup VS Code to launch from the command line

    • For Macs: To allow running VS Code from the terminal using the code command, follow the instructions here

    • For Linux and Windows: This should already be done as part of the installation

  3. Install the following extensions:

    • Dart Code: Support for programming in Dart. It should automatically find the dart-sdk in the Fuchsia tree.
    • FIDL language support: Syntax highlighting support for Fuchsia's FIDL files
    • GN: Syntax highlighting for GN build files
    • Optional but helpful git extensions:
  4. Here are some helpful user settings for Dart. Open your user settings (Ctrl+,), click the ‘{}’ icon in the top left corner and add:

  // Auto-formats your files when you save
  "editor.formatOnSave": true,

  // Don't run pub with fuchsia.
  "dart.runPubGetOnPubspecChanges": false,

  // Settings only when working in Dart
  "[dart]": {
    // Adds a ruler at 80 characters
    "editor.rulers": [

    // Makes the tab size 2 spaces
    "editor.tabSize": 2,


  • Add the Dart plugin by going to Settings > Plugins then searching for Dart language support.
  • Set the Dart path in Settings > Languages & Frameworks > Dart by
    • Check Enable Dart support for the project .
    • Enter the Dart SDK path “${FUCHSIA_SRC}/third_party/dart/tools/sdks/dart-sdk”


If you find that the IDE is unable to find imports (red squigglies) that are already correctly in your dependencies, this is usually a sign that Dart analysis is not working properly in your IDE.

When this happens, try the following:

Open only the project directory you are working on

E.g. only open /topaz/shell/ermine instead of /topaz. The analyzer can have issues with really large source trees.

Remove pub output

  1. Delete the .packages and pubspec.lock files in your project (if present).
  2. Ensure that "dart.runPubGetOnPubspecChanges": false, is present in your VSCode preferences to prevent the files from reappearing whenever a pubspec.yaml file is edited.
  3. Reload VSCode to restart the Dart analyzer.
    1. Press Ctrl+Shift+P to open the VSCode Command Palette
    2. Select “Reload Window”


Delete /out from your Fuchsia directory and rebuild. Dart FIDL bindings are build-generated and may be absent.

Ensure you have a complete build

Any Dart code from packages not included in your build will not be available to the analyzer, so ensure your build configuration (fx set) includes all the packages you need (the --with flag can be helpful.)

Reload the Dart Analyzer

Manually reloading the analyzer is often needed after modifying FIDLs.

VS Code

  1. Open the Command Palette (Ctrl+Shift+P)
  2. Enter and select “Reload Window”

This also restarts the Dart analyzer.


  1. Open Find Action (Ctrl+Shift+A)
  2. Enter and select “Restart Dart Analysis Server”

Check that the correct language has been detected for the current file type

  1. On VS Code use Ctrl+Shift+P then type “Change Language Mode” and ensure it is set to “Auto Detect”.
  2. If this doesn't fix the issue you can try to manually fix via Ctrl+Shift+P and “Configure file association for .dart”

Manually specifying the Dart sdk path

VS Code

Add the line

  "dart.sdkPath": "[YOUR FUCHSIA DIR LOCATION]/third_party/dart/tools/sdks/dart-sdk",

and (Ctrl+Shift+P) “Reload Window”.


  1. Open Settings
  2. Under Languages & Frameworks > Dart, enter “[YOUR FUCHSIA DIR LOCATION]/third_party/dart/tools/sdks/dart-sdk”