Chromium is a free and open-source web browser project, mainly developed and maintained by Google. This codebase provides the vast majority of code for the Google Chrome browser, which is proprietary software and has some additional features. Chromium's logo is identical in shape to that of Google Chrome, but with blue colors instead of being multicolor.
The Chromium codebase is widely used. Microsoft Edge, Samsung Internet, Opera, and many other browsers are based on the Chromium code. Moreover, significant portions of the code are used by several app frameworks.
Google does not provide an official stable version of the Chromium browser, but does provide official API keys for some features, such as speech to text and translation.
Licensing
Chromium is a free and open-source software project. The Google-authored portion is shared under the 3-clause BSD license. Third party dependencies are subject to a variety of licenses, including MIT, LGPL, Ms-PL, and an MPL/GPL/LGPL tri-license.
This licensing permits any party to build the codebase and share the resulting browser executable with the Chromium name and logo. Thus many Linux distributions do this, as well as FreeBSD and OpenBSD.
Differences from Google Chrome
Chromium provides the vast majority of source code for Google Chrome, so the name "Chromium" was chosen by Google because chromium metal is used in chrome plating.
Features
Chromium lacks the following Chrome features: Automatic browser updates API keys for some Google services, including browser sync The Widevine DRM module Licensed codecs for the popular H.264 video and AAC audio formats Tracking mechanisms for usage and crash reports Chromium also has a feature where you can edit the theme, that is also on Chrome.
Branding and licensing
While Chrome has the same user interface functionality as Chromium, it changes the color scheme to the Google-branded one. Unlike Chromium, Chrome is not open-source, so its binaries are licensed as freeware under the Google Chrome Terms of Service.
Development
The Chromium browser codebase contains about 35 million source lines of code.
Contributors
Chromium has been a Google project since its inception, and Google employees have done the bulk of the development work.
Google refers to this project and the offshoot ChromiumOS as "the Chromium projects", and its employees use @chromium.org email addresses for this development work. However, in terms of governance, the Chromium projects are not independent entities; Google retains firm control of them.
The Chromium browser codebase is widely used, so others have made important contributions, most notably Microsoft, Igalia, Yandex, Intel, Samsung, LG, Opera, and Brave. Some employees of these companies also have @chromium.org email addresses.
Programming languages
C++ is the primary language, comprising about half of the codebase. This includes the Blink and V8 engines, the implementation of HTTP and other protocols, the internal caching system, and other essential browser components.
Some of the user interface is implemented in HTML, CSS, and JavaScript. An extensive collection of web platform tests is also written in these languages.
About 10% of the codebase is written in C. This is mostly from third-party libraries that provide essential functionality, such as SQLite and numerous codecs.
Support for mobile operating systems requires special languages: Java for Android, and for iOS both Swift and Objective-C.
In January 2023, Google announced the future use of third-party libraries written in Rust, but this has not yet occurred.
Logistics
The bug tracking system is a publicly accessible website. Participants are identified by their email addresses.
The Chromium continuous integration system automatically builds and tests the codebase several times a day.
Builds are identified by a four-part version number that is major.minor.build.patch. This versioning scheme and the branch points that occur every six to seven weeks are from Google Chrome and its development cycle.
History
2008 to 2010
Google Chrome debuted in September 2008, and along with its release, the Chromium source code was also made available, allowing builds to be constructed from it.