Principal Java Engineer

Responsibilities

• Lead the technical design and architecture of scalable microservices and APIs that support LLM-driven and platform features.
• Drive the evolution of our microservice and event-driven architecture, ensuring system scalability, reliability, and performance.
• Provide technical leadership and guidance to the engineering team through architecture reviews, code reviews, and technical mentoring.
• Collaborate closely with Product, Engineering, and DevOps teams to define technical solutions aligned with business goals.
• Design and oversee the development of retrieval-augmented generation (RAG) pipelines, including document ingestion, embedding generation, vector indexing, and retrieval APIs.
• Ensure high engineering standards through clean code practices, testing strategies, and maintainable system design.
• Champion DevOps and “you build it, you run it” culture, including CI/CD pipelines, infrastructure automation, containerization, and reliable deployment practices.
• Monitor system performance, identify technical risks, and drive continuous improvements in system architecture and engineering processes.
• Maintain required working-hours overlap (at least 5 hours) with the Berlin / Central Europe time zone.
• Contribute as a hands-on technical leader within a multinational Agile development team.

Requirements

• 7+ years of experience in backend development with strong expertise in Java (Java 8+), Spring, Spring Boot, and modern backend architectures.
• Proven experience leading the design and development of large-scale distributed systems or microservices architectures.
• Strong experience with message brokers such as Apache Kafka or RabbitMQ.
• Solid understanding of API design (REST), streaming technologies (SSE/WebSockets/gRPC), and event-driven architecture.
• Hands-on experience with containerization and orchestration (Docker, Kubernetes) and modern CI/CD pipelines.
• Deep understanding of database systems and caching strategies, including PostgreSQL/MySQL, Redis/Memcached, and at least one NoSQL database (e.g., MongoDB, DynamoDB).
• Experience establishing engineering best practices, code quality standards, and testing strategies (unit, integration, functional testing).
• Strong problem-solving, technical leadership, and mentoring skills.
• Excellent communication and collaboration skills.
• Fluent in English.

Nice to have:

• Experience working with AI/LLM systems or RAG architectures.
• Knowledge of AI model evaluation, prompt testing, and A/B testing frameworks.
• Experience implementing Domain-Driven Design (DDD) in large-scale systems.
• Familiarity with Helm charts and Kubernetes ecosystem.

What we offer

• Attractive and competitive performance-based compensation package.
• Full gross salary during probation.
• Generous 13-month salary and dedication bonus.
• Comprehensive healthcare insurance package and annual health check-ups.
• Flexible check-in time before 10:00 AM on weekdays.
• 1-day remote work per week.
• 12 annual leave days, 5 sick leave days, 11 public holidays as required by Vietnamese Labor Law, plus one extra day off for Christmas.
• Opportunity to work on global projects, collaborate with international teams.
• Daily breakfast, Happy Thursday gatherings to connect with colleagues.
• Active sport clubs such as badminton, running, football, music clubs.
• Teambuilding activities, annual company trips, and year end party.
• Continuous learning opportunities through technical & soft skills training, English classes, and internal communities.
• Financial assistance for important life events, including marriage, childbirth, and bereavement, ensuring support at every stage of life.