Benchmark results published by a senior Microsoft engineer have placed a concrete number on a long-running complaint from browser developers and open-web advocates: Apple’s rule requiring all iOS browsers to use its WebKit rendering engine is holding back performance in a meaningful and measurable way.

Kyle Pflug, group product manager for the Microsoft Edge Web Platform, published the data on Monday, June 16, 2026. The results compare a research prototype of Edge — built using Apple’s own BrowserEngineKit framework and running the open-source Blink engine — against Safari on a device running iOS 26.5.1.

On Speedometer 3.1, a widely used browser responsiveness benchmark, the Blink-based prototype scored 49.27 versus Safari’s 38.3, a difference of 28.6 percent. The gap persisted across additional tests.

Benchmark results at a glance

Benchmark Blink prototype (Edge) Safari (WebKit) Difference
Speedometer 3.1 Responsiveness 49.27 38.3 +28.6%
JetStream 3 JavaScript / Wasm 306.35 270.9 +13.1%
MotionMark 1.3.1 Graphics rendering 4,773.52 4,673.68 +2.1%
Pflug was transparent about the limitations of the data: the build tested is a research prototype, not a finished product, and the scores were taken from his personal device rather than a controlled laboratory setting.

Why iOS browsers are all built on WebKit

Since the App Store launched in 2008, Apple has required every browser distributed on iOS to use WebKit, the rendering engine that powers Safari. In practice, this means Chrome, Firefox, Edge, and every other browser on the iPhone are WebKit-based, regardless of what engine they use on other platforms. Performance improvements that Google ships to Blink or Mozilla ships to Gecko never reach iOS users.

Apple introduced BrowserEngineKit in March 2024 to comply with the European Union’s Digital Markets Act, which mandates that alternative browser engines be permitted on iOS in the EU. Microsoft’s prototype was built using this framework. However, more than two years after BrowserEngineKit launched, no browser maker has shipped a non-WebKit engine to actual users. The barriers — technical complexity, App Store rules requiring a separate app for any alternative-engine browser, and the cost of maintaining a distinct iOS build — have so far proved prohibitive.

What the data means

The results illustrate what Open Web Advocacy and others have argued for years: that the absence of engine competition on iOS has a real and compounding cost for users. At the same time, critics of the data point out that prototype browsers do not carry the security mitigations and overhead of production software, and that real-world browsing involves additional scripts that could erode any theoretical advantage.

Apple did not respond to requests for comment on Pflug’s findings. Microsoft described the work as ongoing research rather than a product announcement, and no timeline has been given for a potential public release of a Blink-based Edge for iOS.

Sources: MacRumors, The Register, SquaredTech — June 17, 2026