New Expensify Table of Contents Local Development Platform Specific Setup Testing on browsers in simulators and emulators Running The Tests Additional Reading Application Philosophy API Details Contributing to Expensify Expensify Code of Conduct Contributor License Agreement React StrictMode Left Hand Navigation(LHN) HybridApp additional info & troubleshooting Local development These instructions should get you set up ready to work on New Expensify 🙌 Getting Started 1. Install nvm then node & npm : brew install nvm && nvm install 2. Install watchman : brew install watchman 3. Install dependencies: npm install 4. Run the specific platform with the following command: npm run , e.g. npm run web You can use any IDE or code editing tool for developing on any platform. Use your favorite! Recommended node setup In order to have more consistent builds, we use a strict node and npm version as defined in the package.json engines field and .nvmrc file. npm install will fail if you do not use the version defined, so it is recommended to install node via nvm for easy node version management. Automatic node version switching can be installed for zsh or bash using nvm . Platform Specific Setup For detailed setup instructions for each platform, see the following guides: 🕸 Web Development : Web Setup Instructions 📱 iOS Development : iOS Setup Instructions 🤖 Android Development : Android Setup Instructions Optional AI assisted mobile testing: If you use Claude Code, the /agent device skill drives iOS and Android simulators or devices for interactive testing, debugging, and performance profiling. Requires npm install g agent device . General Troubleshooting 1. If you are having issues with Getting Started , please reference React Native's Documentation 2. If you are running into CORS errors like (in the browser dev console) [安装/使用命令见下方] You probably have a misconfigured .env file remove it ( rm .env ) and try again. Note: Expensify engineers that will be testing with the API in your l