Customize Manifest

After downloading your extension from Extensy, you can open and edit manifest.json directly to unlock browser features that require explicit configuration — like keyboard shortcuts, web-accessible resources, or custom icon sets.

Manual edits to manifest.json are local only. They will not sync back to Extensy. Keep a backup of your edited file before re-generating the extension.

Edit the name, version, and description

Open manifest.json and update the top-level identity fields:

{
  "manifest_version": 3,
  "name": "My Tab Manager",
  "version": "1.2.0",
  "description": "Organize and search your open tabs instantly."
}

Increment version each time you publish an update to the Chrome Web Store.

Add or remove permissions

Add permissions to the "permissions" array to request access to browser APIs. Remove any permissions your extension does not use — the Chrome Web Store flags unnecessary permissions during review. Before:

{
  "permissions": ["storage"]
}

After (adding tabs and alarms):

{
  "permissions": ["storage", "tabs", "alarms"]
}

Some APIs (like "tabs" and "history") require user consent and display a warning during installation. Only include permissions your extension actually needs.

Common permissions and when to use them:

Permission	Use case
`storage`	Read/write `chrome.storage`
`tabs`	Access tab URLs, titles, and states
`alarms`	Schedule recurring tasks
`notifications`	Show desktop notifications
`contextMenus`	Add items to the right-click menu
`activeTab`	Temporary access to the current tab on user action

Adjust content script match patterns

Control which pages your content scripts run on by editing the "matches" array under "content_scripts":

{
  "content_scripts": [
    {
      "matches": ["https://*.github.com/*"],
      "js": ["content.js"],
      "run_at": "document_end"
    }
  ]
}

Specific domain
All HTTPS pages
Multiple domains

"matches": ["https://www.example.com/*"]

Runs only on example.com.

"matches": ["https://*/*"]

Runs on every HTTPS page the user visits.

"matches": [
  "https://*.github.com/*",
  "https://*.gitlab.com/*"
]

Runs on GitHub and GitLab.

Update icon paths

Replace the generated icon placeholders with your own files. Icons must be PNG files at each declared size:

{
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png"
    },
    "default_title": "Open My Tab Manager"
  }
}

Place your icon files in the same directory structure you reference above, then reload the extension in chrome://extensions.

Add keyboard shortcuts

Use the "commands" key to register keyboard shortcuts:

{
  "commands": {
    "toggle-popup": {
      "suggested_key": {
        "default": "Ctrl+Shift+Y",
        "mac": "Command+Shift+Y"
      },
      "description": "Toggle the extension popup"
    }
  }
}

Listen for the command in your background service worker with chrome.commands.onCommand.addListener.

Make assets accessible to web pages

If a content script needs to load images or scripts from your extension package into the page, declare them under "web_accessible_resources":

{
  "web_accessible_resources": [
    {
      "resources": ["images/*.png", "fonts/*.woff2"],
      "matches": ["https://*/*"]
    }
  ]
}

After declaring a resource, reference it in your content script using:

const imgUrl = chrome.runtime.getURL("images/logo.png");

Fundamentals

Advanced Topics

Customize Manifest

Edit the name, version, and description

Add or remove permissions

Adjust content script match patterns

Update icon paths

Add keyboard shortcuts

Make assets accessible to web pages

​Edit the name, version, and description

​Add or remove permissions

​Adjust content script match patterns

​Update icon paths

​Add keyboard shortcuts

​Make assets accessible to web pages

Edit the name, version, and description

Add or remove permissions

Adjust content script match patterns

Update icon paths

Add keyboard shortcuts

Make assets accessible to web pages