Freelance Java Full Stack Developer (Java 21 | Spring Boot | Microservices | PostgreSQL) – Vienna / Remote - Long Term Contract

Java Full Stack Developer (Java 21 | Spring Boot | Microservices | PostgreSQL) – Vienna / Remote

Location: Vienna, Austria (Hybrid: 1–2 days onsite during onboarding, then 2–4 days per month)

Start: ASAP

Duration: 12 months (extension likely)

Workload: Full-time (100%)

Language: English required, German is a plus

Our client are hiring an experienced Java Full Stack Developer with a strong backend focus to join a high-performing agile team delivering scalable, enterprise-grade systems in a modern microservices architecture.

This role is backend-heavy and ideal for developers who enjoy building robust APIs, designing microservices, and working with modern Java and Spring technologies, while contributing to frontend development using React or Angular.

Key Responsibilities

• Design, develop, and maintain backend services using Java 21, Spring Framework, and Spring Boot
• Build and integrate RESTful APIs for internal and external systems
• Develop scalable microservice architectures
• Write high-quality unit tests using JUnit
• Manage builds and dependencies using Maven
• Work with PostgreSQL databases (experience with JSONB is a strong advantage)
• Contribute to frontend development using JavaScript/TypeScript with React or Angular
• Collaborate closely with product owners, architects, DevOps, and cross-functional teams
• Ensure performance, scalability, security, and maintainability of applications
• Continuously improve development processes within an Agile (Scrum/Kanban) environment

Required Skills and Experience

• Strong professional experience in backend development with Java (Java 17/21 preferred)
• Deep knowledge of Spring and Spring Boot
• Solid experience designing and implementing REST APIs
• Strong understanding of microservices architecture
• Hands-on experience with JUnit for testing
• Experience with Maven build management
• Solid knowledge of PostgreSQL (JSONB is a plus)
• Experience with frontend technologies (JavaScript/TypeScript + React or Angular)
• Experience working in Agile teams
• Fluent English (spoken and written)

Nice to Have

• Kubernetes and Helm
• Kafka or Apache ecosystem technologies
• SOAP integration experience
• Graylog or similar logging/monitoring tools
• Telecommunications industry experience

Why Apply

• Long-term project with high extension probability
• Modern Java 21 stack
• Hybrid flexibility with minimal onsite requirements
• International English-speaking environment
• Opportunity to work on scalable, enterprise-level systems

If you are an experienced Java backend-focused Full Stack Developer looking for your next contract opportunity in Vienna with flexible remote work, apply now or contact us directly for a confidential discussion.