Senior Kotlin Backend Developer
Summary
Senior Kotlin backend developer designs, builds, and maintains scalable backend services using Kotlin, Spring Boot, and databases, while mentoring peers and collaborating with clients.
We're looking for a Senior Kotlin Backend Developer to join an international team building scalable backend solutions. You'll take ownership of features from design to production, contribute to architectural decisions, mentor teammates, and communicate directly with the client in English.
Requirements
5+ years of backend development experience
Strong commercial experience with Kotlin
Solid understanding of JVM fundamentals (concurrency, memory management, garbage collection)
Experience with Spring Boot (or Ktor / Micronaut)
Strong knowledge of REST API design
Experience with relational and/or NoSQL databases (PostgreSQL, MySQL, MongoDB, etc.)
Hands-on experience with ORM frameworks such as JPA, Hibernate, or Exposed
Experience writing unit and integration tests using JUnit and MockK
Good understanding of Clean Architecture, SOLID principles, Git, CI/CD, and code review practices
Experience with AI-assisted development tools such as GitHub Copilot, Cursor, Claude, or similar
Upper-Intermediate or higher English (direct communication with clients)
Responsibilities
Design, develop, and maintain backend services using Kotlin
Own features end-to-end, from technical discussions to production deployment
Build clean, maintainable, and well-tested code
Participate in architecture and system design decisions
Review code and mentor other engineers
Collaborate directly with clients and cross-functional teams
Continuously improve development processes and engineering quality
Nice to Have
Experience with microservices architecture
Docker and Kubernetes
Cloud platforms (AWS, GCP, or Azure)
Messaging systems (Kafka, RabbitMQ)
Redis or other caching technologies