Middle Java Engineer (Kotlin)

TL;DR

Middle Java Engineer (Kotlin): Developing and modernizing a scalable ads platform backend using Java 21, Kotlin, and modular monolith architecture with an accent on clean code, scalability, and cloud technologies. Focus on refactoring legacy code, API design, and collaborating within a backend team to build maintainable, testable services.

What you will do

• Develop backend features using Java 21, Spring Boot, Hibernate, and modular monolith architecture moving toward microservices
• Work with legacy code and perform meaningful refactoring
• Write readable, maintainable, and testable code including unit and integration tests
• Collaborate with frontend team to define and evolve API contracts
• Participate in architectural discussions and suggest improvements
• Share knowledge and take responsibility within a backend team

Requirements

• English: Upper-Intermediate (B2) required
• Strong experience with modern Java (Java 17+, ideally Java 21) and Kotlin
• Experience with REST APIs, relational (PostgreSQL) and non-relational (MongoDB) databases
• Knowledge of API authentication workflows (API keys, OAuth tokens)
• Strong cloud development skills (GCP preferred)
• Experience with Docker; Kubernetes knowledge is a plus

Nice to have

• Experience with DSP solutions and AdTech background
• Knowledge of hexagonal architecture and Domain-Driven Design
• Experience working with legacy code and structured refactoring
• Ability to write clean, testable code (SOLID, clean code, unit & integration tests)
• Strong communication skills and readiness to propose improvements
• Ability to collaborate with cross-functional teams and share knowledge

Culture & Benefits

• Equal opportunities in recruitment, career development, and leadership
• Supportive and diverse work environment
• Focus on personal growth and knowledge sharing
• Hybrid work format with multiple locations

Hiring process

• Application review with curiosity and care
• Talent acquisition interview to discuss goals and company support
• Technical interview focusing on expertise and problem-solving
• Customer interview for client-aligned roles
• Job offer and onboarding support