Why Microsoft Abandoned EdgeHTML for Chromium in 2020

In 2020, Microsoft made the monumental decision to retire its proprietary EdgeHTML rendering engine and rebuild the Microsoft Edge browser on top of the open-source Chromium project. This article provides a direct look into the driving forces behind this strategic pivot, which ultimately came down to severe web compatibility issues, the overwhelming market dominance of Google Chrome, developer apathy, a weak extension ecosystem, and the need for cross-platform availability.

The Web Compatibility Crisis

The primary reason for abandoning EdgeHTML was that the modern web was increasingly being built solely for Google Chrome. Because Chrome held a massive majority of the browser market share, web developers focused their efforts on optimizing sites for Blink, the rendering engine inside Chromium. They frequently ignored EdgeHTML. Consequently, many websites functioned poorly or broke entirely when viewed in the original Microsoft Edge.

Furthermore, Google frequently updated its own popular web services—such as YouTube, Gmail, and Google Docs—using code optimized specifically for Chromium. Former Microsoft Edge engineers publicly noted that these changes often degraded performance on EdgeHTML, making Microsoft's browser appear slow and broken to everyday users. Keeping up with Google's constant changes became an unwinnable game of catch-up for Microsoft's engineering team.

Low Market Share and Developer Apathy

When Microsoft launched Edge alongside Windows 10 in 2015, it was meant to wash away the bad reputation of Internet Explorer. However, Edge failed to gain significant traction, stalling at under 5% of the global desktop market share. Because the user base was so small, third-party web developers could not justify the time and money required to test and fix their websites for EdgeHTML. By switching to Chromium, Microsoft ensured that any website optimized for Chrome would automatically work flawlessly in Edge.

A Barren Extension Ecosystem

Modern browser users rely heavily on extensions for ad-blocking, password management, and productivity. The original Edge required developers to build or port extensions specifically for the Microsoft Store, which very few did. By rebuilding Edge on Chromium, Microsoft unlocked immediate compatibility with the massive library of existing Chrome extensions. Users could suddenly install add-ons directly from the Chrome Web Store, eliminating a major barrier to adoption.

Breaking Free from Windows 10 Limitations

The original Edge was deeply integrated into the Windows 10 operating system. This meant the browser could only receive major feature updates twice a year alongside massive Windows 10 OS updates. In contrast, competing browsers updated every few weeks. Additionally, EdgeHTML was locked to Windows 10, leaving behind hundreds of millions of users on Windows 7, Windows 8, and macOS. Moving to Chromium allowed Microsoft to decouple the browser from the operating system, update it rapidly, and release versions for macOS, Linux, and older versions of Windows.

A Shift to Open-Source Collaboration

Under CEO Satya Nadella, Microsoft shifted its corporate philosophy away from strictly proprietary software toward embracing open-source technology. Instead of spending massive resources maintaining a redundant rendering engine that nobody was developing for, Microsoft realized it was more efficient to adopt Chromium and contribute to its development. Since making the switch, Microsoft has contributed thousands of code commits to the Chromium project, improving battery life, memory usage, accessibility, and scrolling performance for both Edge and the wider web.