After reading the Get Started section, use this guide as an outline of extension components, their capabilities in Manifest V3 and how to combine them. First familiarize yourself with what extensions are capable of: core concepts section.
Override Chrome pages and settings
DevTools extensions add functionality to Chrome DevTools by accessing DevTools-specific extension APIs through a DevTools page added to the extension. You can also use the
chrome.notifications API lets you create notifications using templates and show these notifications to users in the user's system tray.
Add keyboard shortcuts
chrome.commands API to add keyboard shortcuts that trigger actions in your extension. For example, you can add a shortcut to open the browser action or send a command to the extension.
chrome.management API provides ways to manage the list of extensions that are installed and running. It is particularly useful for extensions that override the built-in New Tab page.
chrome.omnibox API allows you to register a keyword with Google Chrome's omnibox (address bar).
chrome.downloads API to programmatically initiate, monitor, manipulate, and search for downloads.
Content scripts are files that run in the context of web pages. They use the standard Document Object Model (DOM), to read details of web pages the browser visits, make changes to them, and pass information to their parent extension.
Access the active tab
"activeTab" permission gives an extension temporary access to the currently active tab when the user invokes the extension, for example by clicking its action. Access to the tab lasts while the user is on that page, and is revoked when the user navigates away or closes the tab.
Audio recording and screen capture
Learn about different approaches for recording audio and video from a tab, window, or screen using web platform APIs such as
Modify website settings
An extension service worker (service-worker.js) is an event-based script that the browser runs in the background. It is often used to process data, coordinate tasks in different parts of an extension, and as an extension's event manager.
Understand permissions: how they work and when to avoid asking for them when they're not needed.
Many times content scripts, or other extension pages, need to send or receive information from the extension service worker. In these cases, either side can listen for messages sent from the other end, and respond on the same channel.
In Manifest V3 extensions need to bundle all code they are using inside the extension itself. There are different strategies for doing this.
Chrome Extensions have a specialized Storage API, available to all extension components. It includes four separate storage areas for specific use cases and an event listener that tracks whenever data is updated.
Service workers don't have DOM access. The Offscreen API allows the extension to use DOM APIs in a hidden document without interrupting the user experience by opening new windows or tabs.
Cross-origin isolation enables a web page to use powerful features such as
SharedArrayBuffer. An extension can opt into cross-origin isolation by specifying the appropriate values for the
"cross_origin_opener_policy" manifest keys.