Principal Java Engineer - Backend Platform Hawk-Eye Innovations - Budapest Salary: HUF 1.8M - 2.6M per month Contract: Full-Time, Permanent Location: Hybrid - minimum 2 days per week in office, Budapest ABOUT THE ROLE The Principal Software Engineer (Full-Stack, Backend-leaning) is a senior engineer responsible for the backend architecture, data pipelines, and API layer of a new sports technology product, while remaining capable of contributing to frontend development as needed. This role sits within a small, fast-moving product engineering team and requires someone comfortable owning end-to-end technical delivery across the stack, with backend and data work as the primary focus. WHAT YOU’LL BUILD You will be a core contributor to a new backend platform being built from scratch. The work spans the full data journey - from ingestion at the edge through to storage, transformation, and delivery to end users. Key areas of focus include: - Low-latency data pipelines that ingest and process live sports tracking data, with strict latency requirements for time-critical outputs delivered to coaches and analysts in near real-time. - Event-driven processing using Kafka for streaming data and control messages between on-site devices and cloud services, handling both fast-path live outputs and asynchronous post-processing workflows via SQS and AWS Batch. - Cloud infrastructure on AWS, including Greengrass for edge-to-cloud orchestration, S3 for video and data storage, and Lambda for lightweight processing tasks. - Data transformation and aggregation layers that normalise tracking outputs, store them in a data lake, and make them available to downstream consumers via clean API contracts. - REST and WebSocket APIs that serve both a live data product for immediate consumption and an insights portal for historical analysis and performance comparison. - Observability and reliability - instrumentation, logging, and tracing are built in from the start, not bolted on. The platform needs to run 24/7 without on-site support. KEY RESPONSIBILITIES - Design and build backend services and APIs (REST/WebSocket) supporting data ingestion, transformation, and delivery to frontend and downstream consumers, with particular attention to latency and throughput given real-time processing requirements. - Own data storage and pipeline architecture, including integration with streaming/event infrastructure. - Implement authentication and authorisation in line with the team's chosen cloud identity and access management approach. - Provide technical direction and review for frontend development (React/TypeScript), working closely with frontend engineers to align on approach, component contracts, and data shapes - this is a collaboration and oversight function rather than day-to-day frontend delivery. - Collaborate closely with computer vision/data science engineers to define and consume data contracts. - Participate in technical decision-making for a product in active development, including architecture choices with long-term implications for scale, latency, and maintainability. - Contribute to technical leadership of the wider engineering team, given the seniority of this role. SKILLS AND EXPERIENCE - Strong backend engineering background with production experience in Java (required). - Demonstrated experience building low-latency, high-throughput systems - this is a core requirement, not a nice-to-have. - Working knowledge of a modern frontend framework such as React/TypeScript, sufficient to review and direct frontend work rather than deliver it independently. - Experience with cloud infrastructure and event-driven architectures (e.g. Kafka or equivalent streaming technology). - Experience designing and evolving API contracts (OpenAPI or similar) in a fast-moving, still-evolving product environment. - Familiarity with modern cloud identity and access management approaches (e.g. AWS Cognito or equivalent) is a plus. - Strong communication skills - able to work directly with product and cross-functional stakeholders, and to mentor or direct engineers outside their own core discipline. - Comfortable with ambiguity: this is a build-phase product with evolving scope and infrastructure decisions still being finalised. BENEFITS AND PERKS - Annual leave in line with Hungarian labour law - Hybrid working - minimum 2 days per week in office - Sony Group perks - discounted tickets and events - Cafeteria allowance: SZEP Card, nursery/kindergarten support, MOL Bubi Pass - Private medical, life and accident insurance, dental discounts - Seniority awards and Employee Assistance Programme - All You Can Move fitness pass option EQUAL OPPORTUNITY EMPLOYER Hawk-Eye is committed to fostering an inclusive and diverse workplace. We ensure all employees are treated fairly, regardless of gender, marital status, race, nationality, religion, age, disability, or union membership. We value diversity and strive to create an environment where everyone can reach their full potential. APPLY TODAY If you are passionate about building high-performance backend systems and want to work on real-time data products at scale, we would love to hear from you.