React Native iOS in the browser

Run React Native with Xcode, iOS Simulator, Android Studio, Java, a VM, a long build a browser tab.

SootSim is a clean-room React Native simulator that runs entirely in your browser on canvas, making development, previews, tests and agents 10-100x faster, cheaper, and easier.

DownloadDemo →

Changelog

curl -fsSL https://sootsim.com/install.sh | sh

Runs these apps e2e

Develop

The supercharged React Native Simulator for Humans and Agents

A real React Native simulator that runs in the browser, fast enough for an agent to drive in a loop. The same CLI your tests use lets Claude Code or Codex open the app, read the screen, and act.

Agents drive the simulator through the CLI: describe the screen, tap, type

Inspect any element, the React tree, and network against the live app

Pipe what the simulator sees into Claude Code or Codex and iterate

sootsim

✓ tapped, screen settled in 0.3s

$sootsim do type-into searchInput "labs.bsky"

✓ typed through the iOS keyboard

$sootsim do tap-text "@labs.bsky"

✓ tapped, profile settled in 0.4s

$sootsim wait idle

✓ idle in 0.2s

$sootsim maestro test flow.yaml

✓ launchApp (1.1s)✓ tapOn: composeFAB (0.3s)✓ inputText: "Hello from SootSim" (0.5s)✓ assertVisible: "Post" (0.2s)4/4 steps passed in 6.1s

SootSim25.9s

Maestro + iOS simulator30.4s

agent-device + iOS simulator37.0s

Wall-clock for the same Bluesky flow on every runner.

Test

The richest, fastest React Native test driver

SootSim supports both Maestro and Detox test suites, runs them without any configuration or install, and produces reports that include deep instrumentation into React, React Native, Screens, and Reanimated.

No build step means e2e takes seconds.

Runs Maestro and Detox tests unmodified.

iOS tests on plain Linux for dramatic cost savings.

Previews

Preview builds for every commit, automatic walkthroughs for every PR

Push a branch and a few minutes later your whole org opens the same build as a fully interactive preview, right in the browser.

Branch builds and PR previews land minutes after every push

Each one ships with an AI walkthrough: a video plus a live, steerable demo

Share a link anyone can open with no install, even in iOS Safari

SootSim org dashboard with branch builds and PR previews

Share live previews, App Store screenshots, and beautiful 3d demos.

Automate App Store screenshots with both UI and CLI designers, and share incredible 3D demos right from your browser with presets that make your app stand out.

3D Mode renders your app on a device you can rotate and light

Screenshot Mode covers every App Store device size

One command records a video and an interactive replay

Deep dive

How it all works

Use Cases

Develop any Metro app

0 native build. HMR. Mac, Linux and Windows.

Validated on Bluesky, Uniswap, Expensify, Artsy.

Runs without streaming, even in iOS Safari.

Create live demos in seconds

Record a demo of your app for anyone to test drive.

Watch, pause, and step inside at any point.

Entirely client-side, no server bridge.

See real previews on PRs with AI demos

10x cheaper and faster than real builds.

Fully interactive previews in minutes.

Automatic AI demo, video and interactive.

Cheap Detox and Maestro tests

No build step, CI as cheap as Linux.

Low-cost smoke testing.

Full API coverage of each.

Features

Incredibly fast CLI

Automatic sessions, waits for animations, screens.

80+ React Native-aware actions with better context.

Automatic error surfacing, screen-aware info.

Starts instantly, no build

No rebuilds or reboots, run many devices.

Cold loads in seconds, runs completely local.

No streaming lag from a cloud Mac.

Screenshots and recordings

Record a video + interactive demo in seconds.

Screenshot Mode for easy app store screenshots.

3D Mode for amazing social media demos.

Rapid fire LLM feedback

Inspect → prompt iteratively in seconds.

Claude Code and Codex integration.

Engine

Built like React Native itself

JS, the UI, and iOS chrome each get their own thread.

Scrolls, gestures, and worklets stay smooth while JS works.

Skia, Yoga, Fabric and TurboModules.

Compatibility with receipts

The top 500 native packages all load and run.

The top 100 score 93%, pixel-diff against a real iPhone.

Pure JS never needs a shim. It just works.

iOS and Android, to the pixel

SF Pro optical sizing, emoji, SE to 17 Pro Max.

Keyboard, alerts, sheets, menus, Liquid Glass.

Android gesture nav, platform scroll physics.

The GOATs really work

Reanimated is real, worklets on UI thread.

Gesture Handler and Screens, too.

Keyboard Controller, TypeGPU, Skia, and hundreds more.

FAQ

Ready to build?

Run your React Native app in the browser. No simulators, no native toolchain, no waiting.

curl -fsSL https://sootsim.com/install.sh | sh

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