Stim

Fast, isolated local React Native environments for coding agents.

Stim gives each project or git worktree its own Metro port and owned simulator or emulator. It shares native artifacts, Xcode compilation data, Gradle output, and Metro transforms across worktrees. Agents can work in parallel without sharing live resources, then clean up every resource Stim created.

Stim supports React Native Community CLI and Expo projects. Builds run locally by default; --eas-profile uses completed EAS development builds. Apps can launch on owned simulators and emulators, connected physical devices, or configured remote devices.

Install

The stim npm package installs the stim command. It needs Node 22.12 or later and runs on macOS, Linux and Windows: Android everywhere, iOS locally on macOS or through EAS from any host. See requirements. If you previously installed stim-cli globally, run npm uninstall --global stim-cli first.

npm install --global stim
npx skills add appandflow/stim

Run without a global install when needed:

npx stim <command>

Then ask your coding agent to build and run the app. The normal loop is:

stim doctor
stim start
stim ios                  # or: stim android
stim logs --errors
stim stop

Stim needs no project initialization. Runtime state stays under ~/.stim by default. Getting started covers terms, parallel worktrees, and what to do when a run fails.

Documentation

Read the Stim documentation for the motivation, setup, concepts, command reference, and settings reference.

The installed version also includes its own reference:

stim guide agent
stim guide
stim guide lifecycle
stim guide settings

Packages

• stim provides the stim command.
• @stim-cli/metro shares Metro transforms and records logs.
• @stim-cli/expo-build-cache lets direct Expo builds share native artifacts with Stim.
• @stim-cli/cache holds the cache provider contract and the local-first tier coordination behind both caches.
• @stim-cli/core contains shared internal cache contracts.

Development

pnpm install
pnpm build
pnpm test
pnpm typecheck
pnpm lint

Stim is licensed under the MIT License.

About

App&Flow is a Montreal-based React Native engineering and consulting studio. We partner with the world’s top companies and are recommended by Expo. Need a hand? Let’s build together. team@appandflow.com