Senior Java Backend Developer

Senior Java Backend Developer – Cloud-Native Microservices & Cryptography

We are looking for a Senior Java Backend Developer to lead the design, development, and maintenance of secure, scalable, cloud-native microservices for our Trusted Service Manager (TSM) platform. This role focuses on backend development with Spring Boot 4, cryptographic operations, automation, and test-driven practices in a Kubernetes-based environment.

Key Responsibilities

• Lead the end-to-end development and implementation of TSM backend services and microservices.
• Design, develop, and optimize robust Java backend applications using:
• Spring Boot 4 (including Spring Boot Actuator)
• Spring Cloud
• Spring Data
• Implement and maintain API-first architectures (REST, OpenAPI), ensuring clear contracts and maintainable integrations.
• Build, deploy, and operate cloud-native applications using:
• Docker containers
• Kubernetes (K8s)
• CI/CD pipelines and automation tooling
• Implement secure cryptographic operations, including:
• PKI-based workflows
• X.509 certificate lifecycle management
• Encryption, signing, and key management best practices
• Design data models and access layers using MongoDB for scalable, high-performance storage.
• Drive automated testing and quality assurance:
• TDD and BDD
• Unit, integration, and end-to-end test automation
• Security testing (SAST, DAST)
• Apply and advocate agile methodologies (Scrum), engineering best practices, and secure coding standards.
• Collaborate closely with architects, product owners, QA engineers, and other developers to deliver high-quality solutions.
• Guide and mentor other team members, promoting knowledge sharing and continuous improvement.
• Contribute to observability and operations using Spring Boot Actuator and monitoring/logging tools.

Required Skills & Experience

• University degree in Computer Science, Software Engineering, or a related field.
• Extensive experience as a senior backend Java developer.
• Strong, hands-on expertise with:
• Spring Boot (v4), including Spring Boot Actuator
• Spring Cloud and Spring Data
• Professional experience designing and implementing microservices in cloud-native environments.
• Proficiency in MongoDB, including schema design, performance tuning, and operational considerations.
• Solid knowledge of Docker and Kubernetes for containerized deployments and orchestration.
• Proven track record building API-first solutions:
• RESTful services
• OpenAPI/Swagger specifications
• Deep understanding of cryptography concepts and tooling:
• PKI, X.509 certificates
• Secure key management and cryptographic protocols
• Experience in agile teams (Scrum) with:
• TDD and BDD
• Automated testing strategies
• Security testing (SAST, DAST)
• Familiarity with large-scale, high-availability, enterprise-grade systems.
• Hands-on experience with Atlassian and DevOps tooling:
• Jira, Confluence
• Git (GitLab/GitHub)
• SonarQube, Jenkins, Nexus, Maven
• Strong problem-solving skills, with the ability to troubleshoot complex distributed systems.
• Excellent communication skills and a collaborative, team-oriented mindset.
• Fluent English (spoken and written).

Nice to Have

• Experience developing SDKs (Java or other languages) for external integration.
• Knowledge of client application development (e.g., mobile or desktop clients interacting with backend APIs).
• Background in financial services, payment systems, or digital currency projects.

This role is ideal for a senior backend engineer who enjoys working on secure, high-availability microservices, is comfortable with advanced cryptography, and wants to drive automation and quality across the entire delivery lifecycle.

What we offer

• CULTURE: Join a professional, dynamic environment where collaboration, teamwork, and innovation are valued.
• PHILOSOPHY: Be part of a team where your ideas and contributions have real impact.
• SCHEDULE: Mon–Thu 8:30–17:30h, Fri 8:30–15:30h (1h flexible start time). Hybrid work options available.
• CONTRACT & BENEFITS: Permanent contract, annual training plan, summer intensive schedule, company parking, flexible compensation (transport, childcare, training, health insurance).
• CANTEEN: Onsite cafeteria with breakfast and lunch at subsidized prices.
• LOCATION: El Prat de Llobregat, Mercabarna exit. Accessible via Bus 88/110 from Barcelona or PR4 from El Prat.

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