Rosen Nenov

- Engineered high-performance microservices in Node.js (NestJS) and Python (FastAPI) with RabbitMQ for efficient inter-service communication. - Integrated AI-powered features using OpenAI, including intelligent auto-suggestions, content summarization, and user query understanding, enhancing UX and reducing manual input by 40%. - Built and deployed GraphQL APIs with Apollo Server (Node.js) and Graphene (Python), integrated with Next.js via Apollo Client for optimized AI-enhanced UX. - Designed an authentication microservice with JWT, SSO, and 2FA (Email OTP), deployed on AWS Lambda with AWS CDK for scalable security. - Architected real-time WebSocket infrastructure with Node.js and Redis Pub/Sub, handling thousands of concurrent connections. - Built a component-driven frontend using React 18, Redux Toolkit, TailwindCSS, and TypeScript with SSR, SSG, and ISR for SEO and performance. - Streamlined CI/CD pipelines to accelerate delivery of secure, production-grade features without service disruption. - Wrote comprehensive unit and integration tests using Jest and React Testing Library, achieving 80%+ test coverage and significantly improving UI reliability. - Defined AWS infrastructure with Terraform and orchestrated deployments with Docker & Kubernetes, reducing release cycles. - Mentored junior developers and conducted code reviews, elevating team performance by 30% while maintaining high-quality documentation with Swagger/OpenAPI.

- Migrated a legacy monolith into a modular, cloud-native microservices architecture, applying patterns like Strangler, CQRS, API Gateway, and Saga to ensure reliable service communication and robust transaction handling. - Designed and implemented full-stack SaaS features with React/Next.js (SSR/SSG) on the frontend and modern Python/TypeScript services (Django REST Framework, NestJS) on the backend, deployed via GCP Cloud Run with Firestore for real-time sync. - Built and scaled backend services with PostgreSQL and Redis (BullMQ) to support event-driven workflows and background processing. - Automated CI/CD pipelines with Jenkins, GitLab CI, and Kubernetes, enabling faster, safer releases across AWS and GCP environments. - Used Infrastructure as Code (AWS CDK, CloudFormation, Terraform) to standardize deployments, cutting setup time and reducing infra drift. - Optimized async processing pipelines with SQS/SNS and caching strategies to reduce cold starts and improve throughput. - Partnered with product and design teams to deliver user-facing features under tight deadlines, ensuring high quality with strong testing practices and CI/CD automation.

- Delivered React + Django applications for internal dashboards, client portals, and e-commerce integrations, ensuring scalable, responsive front-ends and reliable back-end systems on PostgreSQL. - Built and optimized RESTful APIs using Django ORM and PostgreSQL, implemented query indexing and batch retrieval to improve performance by up to 50% for large dataset handling. - Enhanced UX and frontend performance, implemented code-splitting, lazy loading, and asset optimization in React to reduce page load times. - Implemented Elasticsearch and MongoDB indexes to improve search and enable real-time reporting. - Automated CI/CD pipelines using Jenkins and Docker-based deployments; created infrastructure-as-code scripts for repeatable, reliable deployments. - Collaborated across teams, coordinated with designers, product owners, and QA to deliver projects on time and within scope while maintaining high code quality and test coverage.

- Contributed to the development of web applications by building responsive UIs using HTML, CSS, and JavaScript, and gradually transitioned into React for building reusable components in single-page applications. - Collaborated with designers and senior engineers to convert Figma/Sketch mockups into clean, accessible, and mobile-friendly frontends, following web standards and UX best practices. - Assisted in backend development using Python, implementing data processing logic and improving system performance through object-oriented design, SOLID principles, and efficient data structures. - Developed and maintained Node.js services with Express and REST APIs, integrating with MongoDB and third-party APIs to support real-time features and improve backend scalability. - Gained early exposure to AWS and GCP, using services such as EC2, S3, and Cloud Functions to deploy and test development builds in cloud environments.