Microsoft published benchmark results on Monday showing that a Chromium-based browser running Apple’s own BrowserEngineKit framework scores 28.6% higher than Safari on the Speedometer 3.1 performance test. The findings raise questions about whether Apple’s 17-year mandate requiring all iOS browsers to use WebKit constrains mobile web performance.
Kyle Pflug, group product manager for the Microsoft Edge Web Platform, compared a research prototype of Edge built with BrowserEngineKit against Safari running iOS 26.5.1. The Blink-based prototype scored 49.27 versus Safari’s 38.3 on Speedometer 3.1. The prototype also outperformed Safari by 13.1% on the JetStream 3 JavaScript benchmark (306.35 versus 270.9) and by 2.1% on the MotionMark 1.3.1 graphics rendering test (4,773.52 versus 4,673.68).
What the numbers mean
Speedometer measures how quickly a browser renders interactive web applications. A 28.6% gap is substantial, especially in a market where incremental performance gains typically amount to single digits. The findings suggest that Safari’s underlying engine may not be optimized to the degree that Chromium’s Blink engine, which powers Chrome and Edge on other platforms, has achieved over two decades of development and competition.
This matters because iOS users cannot install a non-WebKit browser anywhere. Apple requires all iOS browsers to use WebKit, the same engine that powers Safari. Competing browsers like Chrome and Firefox on iPhone are functionally reskinned Safari instances with different user interfaces.
Important caveats about the test
Pflug described the work as a research prototype rather than a finished product, and the numbers as preliminary results from his own device rather than lab conditions. The findings sparked immediate debate in community forums, with skeptics noting the absence of controlled lab testing and questioning whether security and anti-malware measures omitted from the prototype would narrow the performance gap in production code.
No details were provided about the testing environment, repeatability, or whether other variables such as thermal throttling or system load were controlled. Those gaps matter when interpreting a headline percentage.
The regulatory backdrop
The benchmark arrives as Apple faces ongoing antitrust scrutiny over the WebKit requirement. The European Union’s Digital Markets Act, which took effect in March 2024, theoretically required Apple to allow alternative browser engines through BrowserEngineKit. Yet more than two years later, no major browser maker has shipped an alternative engine on iOS.
Companies cite technical barriers and the requirement to publish any such browser as an entirely separate app from their existing WebKit-based version. The combination of regulatory uncertainty, development costs, and distribution complexity has proven sufficient to deter shipping so far.
According to MacRumors, advocacy groups see the Microsoft findings as vindication. Open Web Advocacy told The Register the results illustrate a 17-year cost to consumers. The group called on the European Commission to open a specification proceeding instructing Apple precisely how it must remove barriers to alternative engines, arguing that restricting browser engines allows Apple to limit what the mobile web is capable of and keep businesses dependent on native apps and App Store rules.
The numbers demonstrate what competitive iOS browsers could theoretically deliver. For now, the installed base remains locked into Safari’s constraints.
