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React Native iOS — no Mac necessary.
A 100% web iOS React Native simulator.
Agents 10x faster, simulators 100x cheaper.
Agents 10x faster, simulators 100x cheaper.
npm i -g sootsim
Use Cases
Develop React Native iOS as easy as web
Point sootsim at any Metro server and your unmodified bundle just works — hot reload, and all.
+SootSim unlocks iOS development on Linux and Windows, even in your iPhone's Safari.
+Compatibility is real: we've gotten pixel-perfect on Bluesky, Uniswap, Expensify, and Artsy, running with no modifications.
Record and share live walkthroughs in seconds
One-click to record flows as shareable preview links — a truly usable and real live app + video recording.
+People with the link can watch your flow instantly, but also pause and continue the app at any point.
+Entirely client-side — no server bridge causing your demo to feel slow.
Automatic preview flows on every PR
SootSim PR bot studies what changed, creates a Maestro flow, and posts an inline video + real live demo in minutes.
+An actual test-drivable PR preview link in just a few minutes.
+Plus an inline webm video so your can see your changes without leaving the PR.
Run unmodified Detox and Maestro flows 100x cheaper
Detox and Maestro files run completely unchanged, now your CI is as cheap as headless Chromium on Linux.
+No build step at all.
+Get regression assurance for pennies.
+Keep iOS simulator for the final-mile parity checks.
Features
The fastest, richest CLI for iOS apps
Agents connect, control, and debug in a fraction of the time of the iOS Simulator.
+Smart agentic integration — auto-claims sessions, auto-waits for animations and screens to settle.
+80+ actions designed around React Native, so agents use less context, better. Automatic error surfacing, screen-aware inspect, and more.
Spin up 10 simulators in 10 seconds
Every simulator is just a browser tab. Run as many in parallel as your CPU allows.
+Switch iPhone Pro, Pro Max, SE, mini — no rebuild, no reboot.
+Cold loads in seconds, runs entirely local. No slow streaming delay, no Mac in the cloud to pay for.
Turn local dev into a shareable demo
Hit record, walk through your app, get a /preview/<id> link anyone can watch or step inside.
+Auto-intercepts API calls and assets — playback is fully deterministic, no backend needed.
+Same recording works as a client demo, a bug repro, or visual regression in CI.
Beautiful 3D demos and App Store screenshots
3D mode renders your app on a floating device with thousands of glass, light, and material combos.
+Every preset is a shareable URL. Drop one in your README or PR comment.
+Screenshot mode runs by hand or replays a Maestro flow — exact pt sizes, locales, ready to submit.
Engine
Real multi-worker runtime
Your bundle, the shell, and the page each run on their own thread — same semantics as React Native.
+Animations don't stutter when JS is busy; scroll and gestures stay smooth no matter what your code does.
+Deep optimizations mean lists actually cull, dirty repaints are actually contained, and apps perform suprisingly closely to the real iOS simulator.
Real Reanimated v3 and v4, with real worklets
Not a stub. Worklets run on the UI thread; runOnUI routes between workers exactly like the real one.
+Shared values, animated styles, layout animations, and gesture worklets behave the same as on a device.
+Gesture Handler shares the runtime — pan, pinch, and swipe feel native because the math runs on the UI thread.
Pixel-perfect iOS UI
Status bar, Dynamic Island, keyboard, alerts, sheets, picker, notifications, control center, app switcher, home, lock — all built on pixel-diffing.
+Real Apple emoji, SF Pro Display + Text, and P3 color end-to-end. Type and color match iOS at the pixel.
+Pick any device — iPhone Pro, Pro Max, SE, mini, iPad — at exact pt sizes and safe areas.
Surprising compatibility
220+ native modules work, stubbed against real browser APIs. 350+ pure-JS libraries compose without a shim.
+Reanimated, Gesture Handler, Screens, FlashList, MMKV, WebView, Vision Camera, Skia, Notifee — covered.
+Hundreds of pixel-diff tests run on a real iPhone simulator and sootsim side by side. Browse them at /proof.
Compatibility
Core
99%
127 pixel-checksTop 100
76%
76 of 100 nativeTop 500
25%
125.2 of 500 nativetop 500 native libraries by weekly downloads
verified
works
partial
not yet
native
all
Essentials(6 of 6)
react-native
the framework itself · 54 pixel-checked surfaces97%
react-native-gesture-handler
DrawerLayout (passthrough noop), NativeViewGestureHandler still lacks native-scroll coupling and handlerTag semantics, cross-detector simultaneousWithExternalGesture/requireExternalGestureToFail, ForceTouch semantics are placeholder-only99%
react-native-screens
freezeEnabled/enableFreeze (always false), statusBarStyle/Hidden/navigationBarColor/Hidden ignored, replaceAnimation differentiation, formSheet/pageSheet modal differences, integrated search bar placements99%
react-native-svg
SVG filter primitives (Filter, FeBlend, FeColorMatrix, FeGaussianBlur, FeComposite, etc) — all fe* skipped; ClipPath/Mask/Use/Pattern/Symbol/Image listed as skipped in engine99%
react-native-reanimated
layout animation builders are exported but no enter/exit animation actually plays, useScrollViewOffset returns static 0, useAnimatedSensor static, useReducedMotion always false, useAnimatedKeyboard height tracking returns 099%
react-native-keyboard-controller
per-frame keyboard progress events (smooth `onMove` requires SAB-backed shared values driven from the shell-side keyboard animation; deferred — see plans/real-worklets.md)98%
All Packages(182 of 318)
1-12
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expo-video
player.duration stays 0 (no timeupdate listener), player.currentTime not synced from element, statusChange/volumeChange/timeUpdate events not emitted, useEvent hook not exported, DRM support absent100%
expo-linear-gradient
CanvasKit gradient shader via _gradientColors style prop, full API99%
react-native-pager-view
overdrag (accepted but ignored), offscreenPageLimit (accepted but ignored), pageMargin, keyboardDismissMode, native scroll fidelity (momentum physics differ)99%
expo-image
transition/animation effects, placeholder rendering, blurRadius, contentPosition, sfEffect/SFSymbol, allowDownscaling, autoplay (GIF), responsivePolicy98%
@mozzius/expo-dynamic-app-icon
noop icon switching — correct for browser, useDynamicAppIcon hook is functional100%
@react-native-async-storage/async-storage
full localStorage-backed implementation100%
@react-native-community/checkbox
HTML checkbox input with accentColor tinting100%
@react-native-community/datetimepicker
HTML date/time/datetime-local input; Android imperative API stubbed100%
@react-native-masked-view/masked-view
engine-level masked-view node with canvaskit saveLayer + BlendMode.DstIn alpha compositing100%
@react-native-picker/picker
HTML select element with full Picker API including Picker.Item, modes, focus/blur100%
@welldone-software/why-did-you-render
intentional noop — wdyr mutates React internals and crashes sootsim's bridged React100%
expo-glass-effect
liquid glass via CanvasKit _liquidGlass style descriptor; hooks and availability covered100%
1-12
prev
1 / 16next
verified
works
partial
not yet