Extensions platform vision
Chrome extensions are one of the most-loved and most-used features of the Chrome browser. Extensions can solve a myriad of use cases for a diverse set of users, and in one form or another they are becoming a staple feature of most major browsers.
There's a thriving extension developer community, with hundreds of thousands of published extensions; a strong user base, and millions of extensions downloaded every day. We're going to continue improving and extending this vibrant ecosystem.
This page describes our longer-term vision for the Chrome extensions platform. This helps developers understand and embrace the future direction of the extensions platform.
There have been browser extensions, in one form or another, almost as long as there have been web browsers. Extensions provide a great way to empower users, by adding specialized features and making the browser better for specific users' needs.
The Chrome extension platform was based on a "webby" model to minimize the barrier to developer engagement. It was also conceived to be more secure at its core than previous efforts, by building on web technologies and the web's security model.
Later, Chrome extensions introduced a permissions model to give users finer-grained control what information and resources could be accessed by any extensions they install. The extensions platform also sandboxed extensions in separate processes, providing additional security.
Developers have used our platforms to build a wonderful range of extensions, providing Chrome users with all kinds of enhancements to the browser experience. But the power of the extensions platform has sometimes been exploited to gain inappropriate access to user data and metadata. We see scope for improvement in the privacy and security of extensions; we also intend to focus on performance, while improving extension capability and preserving webbiness.
Where we're headed
The Chrome extensions platform continues to evolve. The specific course we're steering focuses on improvements to security, performance, and privacy — while preserving or extending the capability of extensions and keeping a webby developer experience.
Privacy — Provide ways for extensions to work well without the need to persistently access user data. Improve user control of permissions by informing users what extensions are doing, letting them grant permissions at runtime and in context.
Security — Move toward stricter protocols and requirements for extensions to access resources outside the extension context
Performance — Ensure that extensions work well on all devices: performance issues don't detract from the browser experience, and Chrome runs smoothly even when many extensions are installed.
Webbiness — Embrace the web platform way of doing things, helping to lower barriers to developer engagement, and benefit as the web platform continues to evolve.
Capability — Overall, keep the platform capable, powerful, and feature-rich so extensions can continue to improve and deliver ever-greater value to users.
The developer and user experience
The continued evolution of the extensions platform will result in a matching evolution of the developer and end-user experience. The following sections describe some specific feature avenues we'll be pursuing.
Improved user visibility and control
The extensions platform will provide greater user visibility and control, so that users can more easily manage how extensions access their data and other resources. The platform already begins to address this by:
- Letting the user modify the host permissions granted to extensions
- The extensions menu showing which items can or want to access the current page
We'll continue to improve this user experience. Look for an increasing emphasis on temporary, in-context style of permissions grants, constraining passive access to user data. The introduction of activeTab was an initial step in this direction.
It's also important that users make informed decisions about how their data is handled. We'll be introducing new ways to help users understand what data each extension accesses and how it uses that data, so that users have control of their data.
A new approach to user data access
Many extensions rely on persistent access to user data: the user gives access permission on installation, and the extension can then access the data at any time. We're moving away from this model of persistent access. Instead, we want to let users grant permissions temporarily and only in the context where they're needed.
Beyond that, we'll be providing new API features to help extensions perform work without requiring data access. Chrome's declarativeNetRequest is an example of this approach.
Better alignment with the web platform
Chrome extensions continue to build on and extend web technologies. This helps to minimize obstacles to developer engagement. Look for further adoption of open web capabilities, in addition to extension-specific technologies.
When the Open Web provides a way to achieve a result, the extensions platform will adopt that approach in preference to an extensions-specific approach.
Beyond service workers and promises, expect the extensions platform to continue adopting contemporary web technologies and approaches as they come about. Our intention is to converge with, rather than diverge from, the Open Web.
And of course we'll continue to improve the extensions platform, even beyond the specific goals expressed in this vision. The extensions platform will evolve to address new use cases, add capabilities, and embrace new web features as they come about.
New policies to support these objectives
The extensions platform and the Chrome Web Store will introduce new policies to support the objectives described in this vision. These policies will encourage clearer communication between developers and end users about the privileges that extensions use. Look for new policies that require disclosures, constrain the context for accessing user data, and better enforcement of the extensions single purpose policy.
The vision set forth in this article represents a strategic direction — like a compass heading or north star. Manifest V3 and its associated features are a major step in this strategic direction.
To learn about Manifest V3 itself and its features, see Overview of Manifest V3.
Manifest V3 related changes
There are a number of features that aren't actually part of Manifest V3, but are scheduled for release in the same time frame. These features are related to Manifest V3 in that they impose new requirements that Manifest V3 is designed to address.
The key feature launching in this category is the changing way that host permissions are granted. Again, this isn't an Manifest V3 feature, but it does motivate Manifest V3 changes. Expect these changes in early 2021.
The initial steps in this area have already launched:
- The ability to modify an extension's host access (see Trustworthy Chrome Extensions, by Default).
- Moving extensions out of the right-click menu and into a button on the extensions menu (see A new home for your extensions).
Future related changes
Moving forward, we'll be changing host permissions to be optional by default, with explicit user consent required to grant site access. We'll also be providing new ways for users to defer permission grants until run time, so that users understand the context of the permission being requested. These changes are intended to provide greater user visibility of permissions.