Kostiantyn Makarenko

• Supported and enhanced large-scale telecom-grade microservices built with NestJS, ensuring high availability and reliability of backend systems.

• Designed and implemented scalable APIs handling high-throughput traffic and distributed workloads.

• Contributed to microfrontend architecture using React, enabling modular and independently deployable frontend applications.

• Worked with cloud-native infrastructure (AWS), deploying and maintaining containerized services using Docker and CI/CD pipelines.

• Optimized ETL pipelines and data processing workflows for performance and fault tolerance in data-intensive environments. Participated in system design discussions, focusing on scalability, resiliency, and maintainability of distributed systems.

• Conducted code reviews and contributed to improving engineering standards and best practices across teams. Collaborated in cross-functional and international teams, supporting production releases, client demos, and mission-critical deployments.

• Worked on products for loan issuance and SMB cash flow analytics. The team followed Scrum practices with two-week sprints, demos, retrospectives, and close collaboration with the product owner and QA.
• Worked on a product company developing software for targeted digital advertising and marketing analytics, contributing to the evolution of the platform from early feature iterations to stable, production-ready solutions used by real customers.
• Participated in a Scrum-based development process with two-week sprints, sprint planning, demos, and retrospectives, closely collaborating with product owners, designers, and QA to rapidly validate hypotheses and deliver customer-focused features.
• Took ownership of backend development using Node.js and NestJS, designing and implementing scalable REST APIs and core business logic for ad targeting, campaign management, audience segmentation, and performance tracking, with a strong focus on clean architecture, extensibility, and long-term maintainability.
• Built and maintained automated unit and integration tests across backend and frontend, integrating them into CI/CD pipelines – GitHub Actions – AWS. This significantly reduced regression issues, shortened release cycles, and increased confidence in frequent product updates within a fast-changing advertising domain.
• Improved observability and reliability of NestJS microservices by implementing 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 analytics platform.
• Developed and evolved the frontend using React and Next.js, implementing reusable UI components, campaign configuration flows, dashboards for ad performance analytics, form validation, API integration, global state management, and robust error handling, continuously improving UX and codebase maintainability.
• Managed cloud infrastructure and deployments on AWS, configuring Linux servers, Nginx, reverse proxies, and supporting a microservices-based architecture to ensure scalability, reliability, and high availability as advertising traffic and customer usage grew.

• Worked on client projects across Europe and the US, including internal CRMs, accounting and analytics systems, healthcare, and e-commerce platforms.
• Participated in all stages of the SDLC, from requirements analysis and technical 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 significantly improving system responsiveness and data processing performance.
• Participated in designing and evolving a microservices architecture with event-driven communication using Kafka, improving system scalability, reliability, and enabling gradual decomposition of a monolithic application.
• Actively contributed to applying SOLID principles, Clean Architecture, and continuous code refactoring, improving code readability, maintainability, and testability across the codebase.
• Supported a strong engineering culture through code reviews, pair programming, and internal knowledge sharing via technical workshops and documentation.