JavaScriptCore97.1 smoke score
Nitro
Native macOS baseline through WKWebView, used immediately while background benchmarking runs.
Per-origin engine selection for macOS
A browser that can change its engine.
Morphing Browser I benchmarks Nitro, V8, and SpiderMonkey inside one SwiftUI shell, then picks the best engine for the site you are visiting.
Live modelwww.apple.com
Nitrorun 1/3
V8run 2/3
SpiderMonkeyrun 3/3
Selected engine
Nitro
Chromium / CEFIPC path fixed
V8
Embedded Chromium path with a helper subprocess and renderer-to-browser IPC for benchmark results.
Gecko / Firefox ESR67.8 smoke score
SpiderMonkey
Bundled Firefox ESR runs headlessly through Marionette to measure Gecko's JavaScript path.
Preliminary benchmark snapshot
Results shown, source withheld.
The public site publishes the paper and summary measurements only. The private Swift, CEF bridge, Xcode project, and build scripts stay inside the repository.
Engine
Load / JS / Memory
Composite
Signal
Nitro
JavaScriptCore
361 ms/2 ms/0.0 MB
Score97.1
Winner in the smoke run on www.apple.com.
SpiderMonkey
Gecko
898 ms/0 ms/511.9 MB
Score67.8
Completed through bundled Firefox ESR Marionette.
V8
Chromium
pending/pending/pending
Scoreretest
IPC fix added after timeout finding; ready for a clean re-run.
Architecture
A private engine lab behind a public research surface.
1
User enters a URL and sees Nitro immediately.
2
The benchmark runner spins up isolated sessions for Nitro, V8, and SpiderMonkey.
3
Each engine returns page load, JavaScript time, memory, and failure state.
4
SwiftData stores the winning engine per origin for future visits.
SwiftUI Shell -> Benchmark Runner -> Engine Sessions
Nitro: WKWebView / JavaScriptCore
V8: CEF helper subprocess / renderer IPC
SpiderMonkey: Firefox ESR / Marionette
Industry paper
Read the full system paper.
The PDF covers the abstract, architecture, benchmark algorithm, preliminary results, engineering challenges, and future work for per-origin engine selection.
Published artifact: compiled PDF only. The LaTeX source, app source, and Xcode project are not copied into the Pages build.