Expensify/App is the primary mobile application for Expensify, a corporate expense management platform. It is a cross-platform React Native app (iOS, Android, Web) built with React 19, React Native 0.86, and Expo 57. The app provides a full suite of expense management features: receipt scanning, multi-currency expense reporting, corporate card integration, reimbursement (ACH, global), workspace/policy administration, approval workflows, and accounting integrations (NetSuite, QuickBooks, Xero, Sage Intacct, etc.). The architecture is a typical React Native monolith with a reactive state management layer (react-native-onyx) for offline-first behavior, custom navigation (split/stack/tab), and a rich component library. It includes server-side chart rendering for PDF reports and extensive telemetry via Sentry and FullStory. The codebase is well-structured with platform-specific files, thorough TypeScript typing, and a comprehensive test suite. It is a mature, actively developed application with a large team and community.