• Worked on a product company developing software for targeted digitaladvertising and marketing analytics, contributing to the evolution of theplatform from early feature iterations to stable, production-ready solutionsused by real customers.• Participated in a Scrum-based development process with two-week sprints,sprint planning, demos, and retrospectives, closely collaborating withproduct owners, designers, and QA to rapidly validate hypotheses anddeliver customer-focused features.• Took ownership of backend development using Node.js and NestJS,designing and implementing scalable REST APIs and core business logic forad targeting, campaign management, audience segmentation, andperformance tracking, with a strong focus on clean architecture,extensibility, and long-term maintainability.• Built and maintained automated unit and integration tests across backendand frontend, integrating them into CI/CD pipelines (GitHub Actions + AWS).This significantly reduced regression issues, shortened release cycles, andincreased confidence in frequent product updates within a fast-changingadvertising domain.• Improved observability and reliability of NestJS microservices byimplementing structured logging (Pino/Winston), metrics collection(Prometheus), and dashboards and alerts (Grafana), enabling faster root-cause analysis and reducing MTTR in a high-traffic advertising analyticsplatform.• Developed and evolved the frontend using React and Next.js, implementingreusable UI components, campaign configuration flows, dashboards for adperformance analytics, form validation, API integration, global statemanagement, and robust error handling, continuously improving UX andcodebase maintainability.• Managed cloud infrastructure and deployments on AWS, configuring Linuxservers, Nginx, reverse proxies, and supporting a microservices-basedarchitecture to ensure scalability, reliability, and high availability asadvertising traffic and customer usage grew

• Worked on client projects across Europe and the US, including internalCRMs, accounting and analytics systems, healthcare, and e-commerceplatforms.• Participated in all stages of the SDLC, from requirements analysis andtechnical design to production deployment and post-release support.• Optimized database queries and data access layers (PostgreSQL / MySQL),reducing execution time of critical operations by up to 40% and significantlyimproving system responsiveness and data processing performance.• Participated in designing and evolving a microservices architecture withevent-driven communication using Kafka, improving system scalability,reliability, and enabling gradual decomposition of a monolithic application.• Actively contributed to applying SOLID principles, Clean Architecture, andcontinuous code refactoring, improving code readability, maintainability, andtestability across the codebase.• Supported a strong engineering culture through code reviews, pairprogramming, and internal knowledge sharing via technical workshops anddocumentation.

• Розробка клієнтської та серверної частини веб-додатків