Senior Backend Developer (Kotlin) at Onfy

Berlin, DE

Tech stack: Kotlin, Spring, PostgreSQL, AWS, Kubernetes, Redis, Spark, Scala

Responsibilities

• We’re hiring a Senior Backend Engineer to build and maintain a fast, reliable backend, solve scaling challenges, and own platform architecture

Requirements

• 5+ years of backend engineering experience in production environments

• 3+ years of recent experience with Kotlin or another JVM language

• Strong software architecture skills

• Relational DBMS expertise (PostgreSQL schema design & safe migrations)

• Proven track record in customer-facing product development

• Experience with AI tools and modern AI practices

• Strong written and spoken English
  

Preferred

• Experience as a tech lead or engineering team lead

• AWS / Kubernetes experience

• Observability mindset (metrics, logging)

• Experience with analytics workloads (Spark / Scala)

• Full-stack experience, especially React

We offer

• Compensation package: base salary and performance-based bonuses

• Office-first: flexible hours with a possibility to work remotely 52 days per year, and 28 days of paid annual leave

• Care & Wellbeing: health insurance for the employees, including dental care (Barmenia Mehr Zahn 100), daily meal allowance

• AI-first approach: licenses and access to a wide range of AI tools

• Team & Growth: collaboration with colleagues across Portugal, Brazil, Latvia and China, with opportunities for promotions, professional trainings, and English courses

• Community & Engagement: annual team building activities, knowledge-sharing workshops, and a strong sense of team work