Developed and optimized ONDC-based buyer and seller apps with a focus on backend services.Set up and configured Kafka for efficient inter-service communication, enhancing app performance and scalability.Implemented OTP-based login, address management, cart, and order functionalities, facilitating location-based communication between the app and ONDC sellers.Managed and improved backend services, ensuring robust configuration and development.Utilized MongoDB for data storage, leveraging aggregation pipelines and indexing for optimized queries.Implemented features and enhancements using NestJS, including modules, controllers, services, and middleware.Ensured secure and efficient API development with NestJS, incorporating guards, interceptors, and pipes.Enhanced application performance and scalability with dependency injection and asynchronous programming in NestJS.Created ONDC request and response parameters validator using AJV validation in NestJS with TypeScript.Collaborated closely with cross-functional teams to achieve project deadlines and deliver high-quality features.Conducted parallel testing and debugging to ensure reliability and performance of backend services and App.