Freelance Backend Software Engineer

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)