Senior Backend Java Engineer (Freelance Contract) – Hungary
Contract Length: 3+ Months
Start Date: ASAP
Day Rate: 120,000 HUF – 180,000 HUF per day
Location: Hungary
About the Role
Beyond Sports is looking for an experienced Senior Backend Java Engineer to support the development, scaling, and modernisation of our high-performance backend systems and cloud infrastructure.
This is a hands-on freelance contract opportunity for a senior engineer with deep Java expertise, strong cloud experience, and a passion for building resilient, scalable systems. You’ll work closely with cross-functional engineering teams to refactor core microservices, improve system architecture, and ensure low-latency integrations across our web and mobile platforms.
Key Responsibilities
Design, refactor, and maintain scalable backend microservices and REST APIs using Java and Spring Boot
Re-architect existing backend systems to optimize for maintainability, reliability, and throughput
Implement secure identity, secrets management, and authentication standards across cloud environments
Integrate third-party systems, including real-time sports data feeds, video streams, and commentary providers
Deploy and manage containerised services using Docker and Kubernetes
Provision and maintain cloud infrastructure using Infrastructure as Code (IaC) tools like Terraform
Build, automate, and manage deployment workflows using modern CI/CD pipelines
Monitor, troubleshoot, and optimize application and database performance
Participate in technical planning, architectural discussions, and peer code reviews
Produce clear, maintainable technical documentation for APIs and core backend systems
Required Skills & Experience
Essential
Strong commercial contracting experience with Java and Spring Boot
Proven background building, deploying, and maintaining applications in production cloud environments (AWS or Azure)
Hands-on experience with containerisation and orchestration using Docker and Kubernetes
Expertise in designing and building secure, high-traffic RESTful APIs
Practical experience writing Infrastructure as Code using Terraform
Solid working knowledge of relational and NoSQL databases (e.g., PostgreSQL, MySQL, DynamoDB, Cosmos DB)
Deep understanding of cloud security fundamentals (IAM, secrets management, key vaults)
Experience setting up and maintaining CI/CD pipelines (e.g., GitLab CI, Bitbucket Pipelines, or ArgoCD)
Desirable
Experience with event-driven architectures using Apache Kafka or similar messaging systems
Prior exposure to performance tuning and cloud cost-optimisation strategies
Strong automated testing practices (unit, integration, and regression testing)
Understanding of cloud networking components (VPCs/VNets, API Gateways)