Senior Java Backend Developer

G+D makes the lives of billions of people around the world more secure. We create trust in the digital age with integrated security technologies in three business areas: Digital Security, Financial Platforms and Currency Technology. We have been a reliable partner for our customers for over 170 years with our innovative solutions for SecurityTechAt Payment Technology, our mission is to be at the start of every transaction and to make it secure and simple. We also create contemporary payment and banking solutions for our digital age. As a one-stop shop, we produce and personalise hundreds of millions of payment cards every year and store their "digital twins"
- mobile and digital. Would you like to actively shape the digital transformation with us?About the ProjectJoin a team working on one ofG+D's strategic projects in digital payments: the Digital Euro .
G+D has been selected by theEuropean Central Bank (ECB) as the first-ranked provider for the Digital Euro offline solution, contributing to the development of a key component of the future digital euro infrastructure.
Within this project, you will work on a specializedTrusted Service Manager (TSM) platform, helping ensure that its backend services aresecure, reliable and thoroughly tested .
The core architecture and initial product are already in place. The team is now focused on expanding the platform with new features and building robust automation around it.
SummaryWe are looking for aSenior Java Backend Developerto 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 CloudSpring DataImplement and maintain API-first architectures (REST, OpenAPI), ensuring clear contracts and maintainable integrations.
Build, deploy, and operate cloud-native applications using:Docker containersCI/CD pipelines and automation toolingImplement secure cryptographic operations, including:PKI-based workflowsEncryption, signing, and key management best practicesDesign data models and access layers using MongoDB for scalable, high-performance storage.
Drive automated testing and quality assurance:TDD and BDDUnit, integration, and end-to-end test automationSecurity 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 & ExperienceUniversity 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 ActuatorSpring Cloud and Spring DataProfessional 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:OpenAPI/Swagger specificationsDeep understanding of cryptography concepts and tooling:PKI, X.509 certificatesSecure key management and cryptographic protocolsExperience in agile teams (Scrum) with:TDD and BDDAutomated testing strategiesSecurity testing (SAST, DAST)Familiarity with large-scale, high-availability, enterprise-grade systems.
Hands-on experience with Atlassian and DevOps tooling:Jira, ConfluenceGit (GitLab/GitHub)SonarQube, Jenkins, Nexus, MavenStrong 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 HaveExperience 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 and Diversity: Join a people oriented environment with different nationalities and a great team spirit, flat hierarchies (everyone speaks to everyone). Equa