App Icons

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App Icons

Use public/app-icons to give each configured app its own browser favicon, Apple touch icon, manifest icons, maskable icon, and main UI icon.

The icon system is convention-first. Most apps only need files in a folder named after the AppID:

public/app-icons/<app-id>/
  favicon.ico
  favicon-16x16.png
  favicon-32x32.png
  apple-touch-icon-180x180.png
  manifest-192x192.png
  manifest-512x512.png
  maskable-512x512.png
  ui.png

The boilerplate fallback lives in:

public/app-icons/_default/

If an app-specific asset is missing, 42go falls back to the matching _default asset. Missing app-specific files do not create request-time filesystem checks.

App Config

Most apps can rely on the convention and do not need an icons block.

Use icons only for strict validation or explicit overrides:

const app = {
  name: "My App",
  icons: {
    strict: true,
  },
};

const app = {
  name: "My App",
  icons: {
    basePath: "/app-icons/custom-folder",
    ui: "/app-icons/custom-folder/ui.png",
  },
};

public.toolbar.icon remains the highest-priority override for the toolbar/app-title surface only. It does not change favicons or manifest icons.

Asset Matrix

favicon.ico is the classic browser fallback.

favicon-16x16.png and favicon-32x32.png are browser tab PNG variants.

apple-touch-icon-180x180.png is used by iOS home-screen surfaces.

manifest-192x192.png and manifest-512x512.png are used in the web app manifest.

maskable-512x512.png is used as the manifest maskable icon. Do not crop a normal icon into this shape unless it has a safe area.

ui.png is the default image used by public and protected app title components.

Validation

The _default iconset must be complete. The build fails if a required default asset is missing.

App-specific iconsets may be partial. Missing app assets fall back to _default unless strict validation is enabled.

Use icons.strict: true to fail validation for a single app.

Use APP_ICONS_STRICT=1 to fail validation for all missing app-specific assets.