Manifest

Overview

Sometimes, you'll need to make manual changes to how the manifest.json is generated. You can do this by using the manifest configuration:

// wxt.config.ts
export default defineConfig({
  manifest: {
    // Put manual changes here
  },
});

Manifest Version Compatibility

When defining options in the manifest, always define them for MV3 when possible. WXT will either convert them to their MV2 equivalents or remove them from the generated manifest if there is not MV2 equivalent.

So for fields like web_accessible_resources or content_security_policy, you just need to list them in their MV3 forms. Other fields, like side_panel, which doesn't exist in MV2, will be removed automatically.

Here's an example wxt.config.ts file:

import { defineConfig } from 'wxt';

export default defineConfig({
  manifest: {
    action: {
      default_title: 'Some Title',
    },
    web_accessible_resources: [
      {
        matches: ['*://*.google.com/*'],
        resources: ['icon/*.png'],
      },
    ],
  },
});

And here's the different manifest.json files generated:

MV2

{
  "manifest_version": 2,
  // ...
  "browser_action": {
    "default_title": "Some Title"
  },
  "web_accessible_resources": ["icon/*.png"]
}

MV3

{
  "manifest_version": 3,
  // ...
  "action": {
    "default_title": "Some Title"
  },
  "web_accessible_resources": [
    {
      "matches": ["*://*.google.com/*"],
      "resources": ["icon/*.png"]
    }
  ]
}

Name

If not provided via the manifest config, the manifest's name defaults to your package.json's name property.

Version

The manifest's version and version_name properties are based on the version field listed in your package.json or wxt.config.ts.

• version_name is the exact string listed in your package.json or wxt.config.ts file
• version is the string cleaned up, with any invalid suffixes removed

If a version is not found, a warning is logged and the version defaults to "0.0.0".

Example

// package.json
{
  "version": "1.3.0-alpha2"
}

// .output/<dir>/manifest.json
{
  "version": "1.3.0",
  "version_name": "1.3.0-alpha2"
}

icons

By default, WXT will discover icons in your public directory and use them for the manifest's icons.

public/
├─ icon-16.png
├─ icon-24.png
├─ icon-48.png
├─ icon-96.png
└─ icon-128.png

Icon files need to match the following regex to be automatically included in the manifest. Most design software can output icons in one of these formats

const iconRegex = [
  /^icon-([0-9]+)\.png$/,                 // icon-16.png
  /^icon-([0-9]+)x[0-9]+\.png$/,          // icon-16x16.png
  /^icon@([0-9]+)w\.png$/,                // icon@16w.png
  /^icon@([0-9]+)h\.png$/,                // icon@16h.png
  /^icon@([0-9]+)\.png$/,                 // icon@16.png
  /^icons?[\/\\]([0-9]+)\.png$/,          // icon/16.png | icons/16.png
  /^icons?[\/\\]([0-9]+)x[0-9]+\.png$/,   // icon/16x16.png | icons/16x16.png
];

If you prefer to use filenames in a different format, you can add the icons manually in your wxt.config.ts file:

export default defineConfig({
  manifest: {
    icons: {
      16: '/extension-icon-16.png',
      24: '/extension-icon-24.png',
      48: '/extension-icon-48.png',
      96: '/extension-icon-96.png',
      128: '/extension-icon-128.png',
    },
  },
});

Permissions

Permissions must be listed in the manifest config.

export default defineConfig({
  manifest: {
    permissions: ['storage', 'tabs'],
  },
});

Host Permissions

Host Permissions must be listed in the manifest config.

export default defineConfig({
  manifest: {
    host_permissions: ['*://*.google.com/*'],
  },
});

WARNING

If you use host permissions and target both MV2 and MV3, make sure to only include the required host permissions for each version:

export default defineConfig({
  manifest: ({ manifestVersion }) => ({
    host_permissions: manifestVersion === 2 ? [...] : [...],
  }),
});

Localization

Similar to the icon, the _locales directory should be placed inside the the WXT's public directory.

public/
└─ _locales/
   ├─ en/
   │  └─ messages.json
   ├─ es/
   │  └─ messages.json
   └─ ko/
      └─ messages.json

Then you'll need to explicitly override the name and description properties in your config for them to be localized.

export default defineConfig({
  manifest: {
    name: '__MSG_extName__',
    description: '__MSG_extDescription__',
    default_locale: 'en',
  },
});

See the official localization examples for more details:

• I18n
• Vue I18n

Actions

In MV2, you had two options: browser_action and page_action. In MV3, they were merged into a single action API.

By default, whenever an action is generated, WXT falls back to browser_action when targetting MV2.

Action With Popup

To generate a manifest where a UI appears after clicking the icon, just create a popup entrypoint.

If you want to use a page_action for MV2, add the following meta tag to the HTML document's head:

<meta name="manifest.type" content="page_action" />

Action Without Popup

If you want to use the activeTab permission or the browser.action.onClick event, but don't want to show a popup UI:

1. Delete the popup entrypoint if it exists
2. Add the action key to your manifest:

   // wxt.config.ts
   export default defineConfig({
     manifest: {
       action: {},
     },
   });

Same as an action with a popup, WXT will fallback on using browser_action for MV2. To use a page_action instead, add that key as well:

// wxt.config.ts
export default defineConfig({
  manifest: {
    action: {},
    page_action: {},
  },
});

Full Control

The manifest option can also be set equal to a function, letting you use logical statements to determine what should be output.

// wxt.config.ts
export default defineConfig({
  manifest: ({ manifestVersion, browser, mode, command }) => {
    return { ... }
  }
})

Or, you can use the build:manifestGenerated hook to transform the manifest before it is written to the output directory.

// wxt.config.ts
export default defineConfig({
  hooks: {
    build: {
      manifestGenerated(manifest) {
        // Update the manifest variable by reference
        manifest.name = 'Overriden name';
      },
    },
  },
});