WebKit requirement slows down iOS browser in test Apfelpatient

A benchmark published by Microsoft engineers suggests that Apple's requirement to force all iPhone browsers to use its own WebKit engine is noticeably impacting performance. An Edge prototype running its own engine performed almost 30 percent better than Safari in Apple's own speed test. More than two years after opening up the DMA (Digital Access Management) interface, no vendor has yet released an alternative engine for iOS.

Apple has always stipulated that every browser on the iPhone must use its own WebKit engine – the same technology that powers Safari. Chrome or Firefox on the iPhone are therefore technically little more than rebranded versions of Safari. The EU's Digital Markets Act was supposed to change this, but reality shows just how mixed the DMA's consequences actually are for Apple. Now, for the first time, concrete benchmark results from Microsoft confirm the significant performance difference between WebKit and an open-source engine.

Almost a 30 percent lead in Apple's own test

Kyle Pflug, Group Product Manager for Microsoft Edge's web platform, published the results on Monday. The test compared a research prototype of Edge, built with Apple's BrowserEngineKit framework, against Safari running iOS 26.5.1. In the Speedometer 3.1 test - a benchmark developed by Apple - the Blink-based prototype scored 49.27 points, while Safari scored 38.3. This represents a lead of 28.6 percent.

The prototype also came out on top in other disciplines. In the JavaScript benchmark JetStream 3, the difference was 13.1 percent (306.35 compared to 270.9), and in the graphics rendering test MotionMark 1.3.1 it was 2.1 percent (4,773.52 compared to 4,673.68).

A research prototype, not a finished app

Pflug himself cautiously interpreted the figures. He explained that it was a research prototype, not a finished product; the values were preliminary and obtained on his own device, not under laboratory conditions. The general gap in favor of the open-source engine thus remains a clear indication, but not yet a conclusively reliable measurement.

Why all iOS browsers run on WebKit

WebKit is Apple's core browser engine and is found not only in Safari but also in numerous other apps – a fact recently highlighted by a security update containing no fewer than 20 WebKit patches. Because Apple mandates the engine for all iOS browsers, Chrome, Firefox, and the other providers share the same technical foundation. While they may look different, under the hood they all render using WebKit.

Two years of DMA – and no alternative engine

Theoretically, this situation changed in March 2024. The Digital Markets Act obligates Apple to allow alternative browser engines via the BrowserEngineKit framework. However, more than two years later, not a single browser manufacturer has delivered such an engine to iOS. The companies cite technical hurdles – and the requirement to release a browser with its own engine as a completely separate app alongside the existing WebKit version.

The call for an investigation by the EU Commission

The Open Web Advocacy initiative, speaking to The Register magazine, assessed the findings as evidence of harm that has plagued consumers for 17 years. The group called on the European Commission to initiate a specification procedure that would precisely dictate to Apple how to remove the barriers to alternative engine development. Restricting users to a single engine allows Apple to limit the possibilities of the mobile web and keep businesses dependent on native apps and the rules of the App Store.

Why the dispute goes beyond mere measurements

Behind the benchmark figures lies a more fundamental question: How powerful the mobile web on the iPhone is allowed to be is, in effect, decided solely by Apple. As long as every engine has to use WebKit, the performance of competing browsers remains tied to Apple's pace. For Apple, the unified engine is a security and privacy argument; for critics, it's a competitive lever that stifles high-performance web apps and protects the app market. The newly presented measurements provide concrete figures for this debate for the first time – and are likely to increase regulatory pressure in Europe rather than decrease it. (Image: Shutterstock / jakir143)