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Fast, isolated React Native environments for agents

Give each coding agent a fast, isolated React Native environment. Stim shares build caches across worktrees, owns each device and port, supports local and remote simulators, and cleans up when the work is done.

Get started
npm install --global stim
stim <command>

Fast builds across worktrees

Native artifacts, Xcode compilation data, Gradle output, and Metro transforms are shared safely. A new worktree can install a cached app when its native inputs match. Concurrent misses use one build.

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Parallel agents without collisions

Each checkout gets its own Metro port and owned device. Agents can create isolated git worktrees and work in parallel. Small, streaming output and focused errors reduce waiting and token use.

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React Native and Expo, here or remote

Stim works with React Native Community CLI and Expo projects. It builds locally, then launches on an owned simulator or emulator, connected phone, or configured remote device. The agent gets the exact device and launch state.

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Owned resources and complete cleanup

Stim tracks every port, process, build, device, and remote session it creates. stop, worktree remove, and gc reclaim resources without touching devices Stim does not own.

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Why Stim​

React Native toolchains were built for one developer working in one checkout. Coding agents often work across several worktrees at once. Stim lets those worktrees share build work while keeping their devices, ports, and running apps separate.

More about Stim

Give your agent the skill​

npx skills add appandflow/stim

Then ask your agent: "Build and run the app on iOS."

Stim needs no initialization. Runtime state stays outside the project.

Agent setup