Hack The Box is seeking a Senior Java Engineer to design and implement the microservices foundation that transforms how we build software. You will lead by example, creating robust and secure Spring Boot services while helping teams adopt resilience and integration patterns. Your work will shape foundational architectural decisions and service boundaries.

What You'll Do

Design and build new Spring Boot microservices, applying patterns that ensure consistency, resilience, and scalability.
Shape the API Gateway layer, enabling secure routing, composition, and cross-cutting concerns for our platform.
Collaborate with architects and teams to define service boundaries and integration strategies aligned with business needs.
Modernize legacy systems incrementally using strangler fig and anti-corruption layer patterns.
Champion code quality through reviews, best practices, and hands-on guidance that elevates the entire team.
Partner with SRE, Platform, and QA to keep services observable, testable, and production-ready.
Contribute to architectural decisions, documenting trade-offs and communicating direction clearly.
Mentor fellow engineers, sharing knowledge on microservices, Spring ecosystem, and clean code practices.

What We're Looking For

Solid experience with Java and the Spring ecosystem (Spring Boot, Spring Cloud, Spring Data, Spring Security) in production environments.
Hands-on experience designing and building microservices, with practical knowledge of patterns like Saga, CQRS, Transactional Outbox, and API Gateway.
Strong understanding of distributed systems challenges—data consistency, service communication, resilience, and fault tolerance.
Experience with messaging systems (e.g., Kafka) and event-driven architectures.
Familiarity with containerization and orchestration (Docker, Kubernetes) and CI/CD pipelines.
Ability to communicate architectural decisions clearly, whether through diagrams, documentation, or conversations with technical and non-technical stakeholders.
A track record of mentoring or guiding other engineers.

Technical Stack

Java, Kotlin
Spring ecosystem
API integration styles
Relational databases, noSQL
Docker, Kubernetes
Git, GitHub, Jira

Team & Environment

You'll join a fully autonomous, high-performing team of senior engineers and architects. This backend-oriented but T-shaped team operates with an agile mindset, taking ownership end-to-end, and you will be reporting to Senior Architects.

Benefits & Compensation

Private insurance
25 annual leave days
Dedicated budget for training and professional development, including participation in conferences
State-of-the-art equipment (Macbook, iPhone, and mobile plan)
Free lunch & snacks at the office
Full access to the Hack The Box lab offerings
Flexible/Hybrid working

Work Mode

This role follows a hybrid work model and is based in Greece.

At Hack The Box, we are committed to fostering a diverse, inclusive, and equitable workplace. We believe that diversity enriches our performance, services, and the communities we serve. As such, we ensure that all job applications are considered solely based on merit, skills, and qualifications. We do not discriminate on grounds of race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.