Open to opportunities

Денис Варенников

@0001474

Message

Skilled backend developer building scalable APIs and cloud-native systems.

Ukraine

Message

What I'm looking for

I seek backend roles focusing on scalable systems, API design, and cloud-native infrastructure in collaborative, agile teams where I can drive performance and reliability improvements.

I am a backend developer with 5+ years of experience building scalable, high-availability systems for international companies. I specialize in API design, cloud infrastructure, and database optimization, and I deliver reliable solutions across remote and hybrid teams.

I've led backend development for an e-commerce platform handling over 500,000 daily users, implemented real-time notifications with Redis and RabbitMQ, and optimized GraphQL and REST endpoints to significantly improve response times. I design CI/CD pipelines with GitLab CI and Jenkins to speed deployments and ensure stable rollouts.

I have built microservices in Go that process 10 TB/day, migrated monoliths to resilient microservices architectures, and improved database performance through advanced PostgreSQL optimizations. I thrive in agile environments, collaborate across time zones, and am passionate about performance and reliability.

Experience

Work history, roles, and key accomplishments

Current

Backend Developer

Current

CentrySoft

Jan 2022 - Present (4 years 5 months)

Led backend development for a high-availability e-commerce platform handling over 500,000 daily users; implemented real-time notifications and optimized APIs to reduce latency by 35% and speed up key endpoints by 50%.

Ruby on Rails Go Redis GraphQL MySQL PostgreSQL Docker Kubernetes Gitlab CI

Backend Engineer

Avatar Engines

Jun 2017 - Dec 2021 (4 years 6 months)

Developed Go microservices for a data processing pipeline handling 10 TB/day and led migration of a monolith to microservices that increased uptime by 50% and improved query performance by up to 45%.

Go Microservices AWS Lambda PostgreSQL Kafka Docker CI CD Data Processing Performance Optimization

Junior Backend Developer

Berezha Security Group

Mar 2015 - May 2017 (2 years 2 months)

Built backend services in C# and ASP.NET that automated internal processes, reducing operational costs by 15% and improving delivery of features in a hybrid remote environment.