React Native iOS, in the browser — SootSim

✕

React Native iOS — no Mac, no XCode.

Delete the time, cost, and pain of native development.SootSim makes simulators 100x cheaper and agents 10x faster.
It's a clean-room, web-powered React Native simulator with near pixel-perfect conformance on all popular libraries and apps.

Download (macOS)Live demo →Docs ↗

macOS (Intel)Linux (x64)

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.

+Develop on Linux and Windows.

+Bluesky, Uniswap, Expensify, Artsy — pixel perfect.

+No streaming, even runs in iOS Safari.

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.

+Watch, pause, and step inside at any point.

+Entirely client-side — no server bridge.

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.

+Test-drivable preview link in minutes.

+Inline webm video — no 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.

+Regression assurance for pennies.

+Keep iOS sim for final-mile parity.

Features

The fastest, richest CLI for iOS apps

Agents connect, control, and debug in a fraction of the time of the iOS Simulator.

+Auto-claims sessions, auto-waits for animations and screens.

+80+ React Native-aware actions — less context, better outcomes.

+Automatic error surfacing and screen-aware inspect.

Spin up 10 simulators in 10 seconds

Every simulator is just a browser tab. Run as many in parallel as your CPU allows.

+Switch Pro, Pro Max, SE, mini — no rebuild, no reboot.

+Cold loads in seconds, fully local.

+No streaming lag, no Mac in the cloud.

Turn local dev into a shareable demo

Hit record, walk through your app, get a preview link anyone can watch or step inside.

+Auto-intercepts API calls and assets — fully deterministic.

+One recording: client demo, bug repro, or CI regression.

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 in a README or PR.

+Screenshots: by hand or replay a Maestro flow.

+Exact pt sizes and 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, scroll, and gestures stay smooth when JS is busy.

+Lists cull, repaints stay contained — close to native iOS.

Real Reanimated v3 and v4, with real worklets

Real Reanimated code, real UI vs main thread runtime semantics. No polyfills involved.

+Shared values, animated styles, layout animations — device-faithful.

+Gesture Handler on the same runtime — pan, pinch, swipe feel native.

Pixel-perfect iOS UI

Status bar, Dynamic Island, keyboard, alerts, sheets, picker, notifications, control center, app switcher, home, lock — all built on pixel-diffing.

+Apple emoji, SF Pro, P3 color — pixel-matched to iOS.

+Pro, Pro Max, SE, mini, iPad — 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.

+Real iPhone vs sootsim, pixel-diffed side by side. See /compat.

Validated Compatibility

Core

99%

135 pixel-checks

Top 100

77%

77.4 of 100 native

Top 500

28%

138.6 of 500 native

top 500 native libraries by weekly downloads

verified

works

partial

not yet

How it works: Validation of popular native packages. We don't validate JS-only packages beyond a few high value ones as most "just work" due to high Core conformance.For native packages, we use unit and integration testing to estimate a baseline. Then, for React Native and other high value packages, we also run true pixel-diff. The final score combines both.

native

all

Essentials(6 of 6)

react-native

the framework itself · 58 pixel-checked surfaces

98%

react-native sootsim

react-native ios

react-native-gesture-handler

DrawerLayout (passthrough noop), NativeViewGestureHandler still lacks native-scroll coupling and handlerTag semantics, cross-detector simultaneousWithExternalGesture/requireExternalGestureToFail, ForceTouch semantics are placeholder-only

99%

react-native-gesture-handler sootsim

react-native-gesture-handler ios

react-native-screens

freezeEnabled/enableFreeze (always false), statusBarStyle/Hidden/navigationBarColor/Hidden ignored, replaceAnimation differentiation, formSheet/pageSheet modal differences, integrated search bar placements

99%

react-native-screens sootsim

react-native-screens ios

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 engine

99%

react-native-svg sootsim

react-native-svg ios

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 0

99%

react-native-reanimated sootsim

react-native-reanimated ios

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%

react-native-keyboard-controller sootsim

react-native-keyboard-controller ios

All Packages(193 of 335)

1-12

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1 / 17

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expo-linear-gradient

CanvasKit gradient shader via _gradientColors style prop, full API

100%

expo-linear-gradient sootsim

expo-linear-gradient ios

react-native-pager-view

overdrag (accepted but ignored), offscreenPageLimit (accepted but ignored), pageMargin, keyboardDismissMode, native scroll fidelity (momentum physics differ)

94%

react-native-pager-view sootsim

react-native-pager-view ios

expo-image

transition/animation effects, placeholder rendering, blurRadius, contentPosition, sfEffect/SFSymbol, allowDownscaling, autoplay (GIF), responsivePolicy

92%

expo-image sootsim

expo-image ios

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 absent

89%

expo-video sootsim

expo-video ios

react-native-webview

actual web content rendering inside the canvas worker, onShouldStartLoadWithRequest, allowsBackForwardNavigationGestures, userAgent, dataDetectorTypes, cacheEnabled, incognito, scalesPageToFit, canGoBack/Forward in iframe-mode (always false), originWhitelist enforcement

55%

react-native-webview sootsim

react-native-webview ios

@mozzius/expo-dynamic-app-icon

noop icon switching — correct for browser, useDynamicAppIcon hook is functional

100%

@react-native-async-storage/async-storage

full localStorage-backed implementation

100%

@react-native-community/checkbox

HTML checkbox input with accentColor tinting

100%

@react-native-community/datetimepicker

HTML date/time/datetime-local input; Android imperative API stubbed

100%

@react-native-masked-view/masked-view

engine-level masked-view node with canvaskit saveLayer + BlendMode.DstIn alpha compositing

100%

@react-native-picker/picker

HTML select element with full Picker API including Picker.Item, modes, focus/blur

100%

@welldone-software/why-did-you-render

intentional noop — wdyr mutates React internals and crashes sootsim's bridged React

100%

1-12

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verified

works

partial

not yet

Pricing

Personal

Desktop app, cloud share, auto PR previews. Billed yearly only. $99/year.

100 shares / month

10 PR previews / month

API key for local + personal CI/CD

Subscribe

Team

Team access, pooled cloud share and auto PR previews. 3-seat minimum, add more anytime. $19/seat/mo $14/seat/mo billed yearly.

100 shares / seat / mo, pooled

10 PR previews / seat / mo, pooled

Agentic automatic flows on PRs

Start Team

Free

Free OSS CLI with browser simulator. Includes a 14-day trial with desktop app, cloud share, and auto PR previews.

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