To develop an app like Karrot for local buying and selling, focus on key features like user profiles, item listings, secure payment gateways, real-time messaging, and geolocation for proximity-based transactions. Ensure an easy-to-use UI/UX design with intuitive navigation and search filters. Implement features like rating and review systems to build trust. Choose a robust tech stack such as React Native for cross-platform apps or native technologies like Swift and Kotlin. Integrate chat systems for secure communication and real-time updates. Prioritize security for user data and payment protection. For expert development insights, explore Dev Technosys for guidance on building scalable, user-centric apps.