Join neXa – Let’s Shape the Future Together!
Position: Backend Engineer (Kotlin)
At neXa, we’re not just building digital solutions — we’re helping businesses grow smarter. We work with forward-thinking clients across industries to design, build, and implement technology that makes a real difference. From intelligent automation to custom applications, our projects are as diverse as our team.
We’re now looking for a Backend Software Engineer to join a high-energy engineering team working on large-scale advertising and recommendation systems. This role focuses on building highly scalable backend services responsible for processing massive volumes of advertising data with low latency and high reliability.
You will contribute to the development of modern microservice-based systems powering intelligent ad delivery, real-time event processing, and high-performance data-driven solutions within a complex distributed environment.
Scroll down to see the full job description, including responsibilities and requirements:
Responsibilities:
- Design, develop, and maintain backend services and APIs using Kotlin and Spring Boot
- Build scalable microservice-based systems handling high-volume traffic and real-time event processing
- Develop solutions for intelligent ad selection, bidding, and content delivery
- Process and manage large streams of advertising and analytics events
- Design architecture for new modules and improve existing backend systems
- Write clean, maintainable, and high-quality production code
- Collaborate with Product Managers, Data Analysts, UX Designers, and other engineering teams
- Participate in code reviews, technical discussions, and engineering best practices
- Create and maintain unit and integration tests
- Support operational stability, monitoring, and on-call activities
- Contribute to scalability, performance optimization, and system reliability initiatives
Requirements:
- 4+ years of commercial backend development experience
- Strong knowledge of Kotlin and Spring Boot
- Experience designing and implementing microservice architectures
- Hands-on experience with MongoDB or other NoSQL databases
- Experience designing, building, testing, and maintaining backend APIs and services
- Strong understanding of scalable backend system design and distributed systems
- Experience collaborating with technical and business stakeholders
- Strong engineering mindset and experience with code reviews and technical documentation
- Good analytical and problem-solving skills
- Polish at min. C1 level and English at B2+ level
Nice to have:
- Experience with reactive programming
- Experience with Couchbase and Elasticsearch
- Experience with Google BigQuery or Data Warehouse solutions
- Experience writing advanced unit and integration tests using Kotest or Spock
- Experience with high-traffic or low-latency systems
- Familiarity with event-driven architectures and stream processing systems