Ivan Kalinin

Senior Golang Developer @Ozon Tech

Warsaw, PL

Development of a Software Solutions in Biggest E-com in CIS.Hands-on experience designing microservices architecture, REST APIstructure & DB scheme.Tech Stack- Go- Postgres- Kafka- Memcached- S3- Prometheus, Grafana- Kubernetes- Created and optimized database schemas for Postgres, reducing query execution time by 35.4% through proper indexing and schema redesigning- Developed a tool that reduced feature development time for mobile and frontend engineers by 34%, enabling them to work on the internal website designer without needing to deploy vertical services- The project was adopted by over 150 engineers across multiple teams, leading to 27% faster iteration cycles and 15% fewer deployment dependencies- Participated in optimizing site localization, moving translation services closer to the client. This change improved translation loading times by 24% and reduced server-side processing by 12.1%, resulting in a smoother user experience for over 5 million users across 5+ languages- Implemented filtering of inefficient data provider requests, reducing RPS for one service from 60k to under 1, and for another from 47k to approximately 6k, while also cutting CPU and memory usage by 30–50%- Built automatic CSRF protection by introducing strict HTTP method validation in over 1,300 handlers, eliminating potential vulnerabilities- Automated the update of the \"showroom\": kept data on key business entities up to date, increasing coverage to 60–70% and reducing manual effort- Regularly took on-call shifts, completed 300+ tasks related to incident response and support, actively responded in the developer support chat, performed code reviews, advised teammates, participated in task estimation, and presented results at demos — all of which had a positive impact on the base factor and team development.

Moscow State University

Bachelor's degree