Device Synchronization Mechanism Implementation

# Full-Stack Developer – Cross-Device Data Synchronization ## Project Overview We are seeking an experienced developer to design and implement a secure cross-device synchronization solution for a React web application and a React Native mobile application. The applications generate and store machine-learning data locally, including: * Face embeddings * Vector embeddings * Media metadata * Timestamps and version information Current storage technologies: * Web: IndexedDB * Mobile: SQLite The goal is to synchronize this data across a user's authorized devices while minimizing data transfer and maintaining security and data integrity. ## Key Requirements ### Device Discovery * Detect authorized devices belonging to the same authenticated user on a local network. * Support Web-to-Mobile, Mobile-to-Web, and Mobile-to-Mobile synchronization. ### Delta Synchronization * Transfer only new or updated records. * Avoid full database transfers whenever possible. * Use an efficient change-tracking mechanism such as IDs, timestamps, versioning, or a recommended alternative. ### Bi-Directional Sync * Synchronize data in both directions. * Ensure devices exchange missing embeddings, vectors, and metadata. * Keep all authorized devices updated with the latest available records. ### Sync Triggers Synchronization should occur: * At application startup * Upon user login * When a user selects “Sync Now” * Optionally when a new authorized device is discovered ### Data Integrity & Security * Prevent duplicate records. * Validate imported data before storage. * Handle interrupted transfers and recovery. * Encrypt data during transfer. * Restrict synchronization to devices belonging to the same authenticated user. ## Responsibilities * Design the overall synchronization architecture. * Implement synchronization functionality in React and React Native. * Build any required synchronization services or APIs. * Recommend the best approach for: * Device discovery * Delta detection * Data transfer format * Conflict resolution * Scalability for large datasets * Create documentation and test cases. ## Deliverables * Solution architecture and design documentation * React implementation (Web) * React Native implementation (Mobile) * Synchronization service/API components * Deployment and maintenance documentation * Test plans and validation results ## Preferred Experience * React and React Native * IndexedDB and SQLite * Offline-first applications * Data synchronization systems * WebRTC, WebSockets, local networking, or peer-to-peer communication * Data versioning and conflict resolution * Secure data transfer and distributed systems The solution should be lightweight, efficient, scalable, and optimized for incremental synchronization of large embedding and metadata datasets between authorized user devices.