Kotlin Backend Engineer

We are looking for a skilled Kotlin Backend Engineer for service agreement collaboration. B2B Sales & Distribution team builds and operates the backend platform powering Flix's partner-facing ecosystem — including a self-management platform for partners, a back office portal for internal users, and an AI agentic bot supporting partner operations. The team is driving a significant modernization of its backend architecture and is working in an AI-native development environment. Scope of services Independent delivery of backend services in Kotlin and Spring Boot, including design, development, and maintenanceBuilding and maintaining REST APIs used by internal and external partnersContributing to architectural decisions and technical modernization initiatives as a senior topic driverImproving observability, performance, and reliability of backend systems using DataDogSupporting CI/CD pipelines and cloud infrastructure on AWS and KubernetesWorking within an AI-native development environment, including CI-integrated code review automation and an internal Claude Code plugin marketplace covering Kotlin/Spring Boot conventions, architectural patterns, testing practices, and database guidelinesSharing Kotlin expertise and best practices with existing engineers on the Flix team who are transitioning from other languages, through code review, pairing, and technical guidance Relevant expertise 4+ years of software engineering experience, primarily backend development with a JVM language, including some commercial experience with KotlinHands-on Spring Boot experienceExperience building and maintaining REST APIs and distributed systemsSolid SQL knowledge and relational database design, including MySQL and PostgreSQLSound software engineering fundamentals and clean code practicesClear written and spoken English communication skillsPreferred experience with: AWS, Kubernetes, GitLab CI/CD, Kafka, Terraform, LLM integrations, RAG systems, AI product development, or legacy system migration experience Collaboration model Cooperation based on a service agreement with independent delivery of agreed services and invoicing