Sergei Lazeev

At Okko, I own backend services end-to-end, from partner requirements and API design through production delivery and support. I delivered a partner-facing promo-code platform that drove 10,000+ new user activations within three months.

I built an asynchronous integration for partner gamification campaigns and, as its sole owner, fixed a Kafka queue bottleneck with a Postgres-polling relay. I also owned the backend for Multi-Subscription, splitting the scope into four microservices and building a join mechanism that served 100,000+ users in its first month with no lost or duplicate joins.

Earlier at Okko, I designed and built a dynamic configuration service that eliminated redeployments for parameter changes, and created an automated load-testing workflow for eight Gradle microservices. As a freelance Junior Backend Developer, I developed bots for Telegram and Discord, including an eSports tournament platform and an auto-parts booking bot.

At ITMO University, I mentor undergraduate students and review code for courses in Java, Web Programming, and Software Engineering. My work centers on Kotlin and Java backend engineering, distributed systems, and high-load services.