Senior Java Developer

iKnowHow Group is a leading Software & Robotics Solutions group of companies operating internationally for over 24 years, with 300+ professionals delivering innovative technology solutions across Energy, Telecommunications, Banking & Financial Services, and Public Sector industries. The group is structured into specialized subsidiaries, each focused on distinct technology domains and market verticals.

iKnowHow S.A., as the cornerstone of the group, utilizes state-of-the-art technologies and handles end-to-end internal and external project development, from conception to completion. Our portfolio spans Data & AI platforms, enterprise integration, cloud-native applications, and digital transformation initiatives for major organizations in private and public sectors.

We are now looking for a Senior Java Developer with strong technical skills and solid working experience to work in outsourced challenging projects.

Responsibilities:

• Design and build a centralized authorization system that governs identity validation and access decisions across the platform

• Implement business policy and transaction controls in a way that keeps other services simple and decoupled from security logic

• Ensure all security-relevant actions are logged, traceable, and auditable to meet enterprise compliance standards

• Optimize the system for high-speed, low-latency decision-making at scale

• Architect for high availability and resilience, ensuring the system keeps functioning during upstream outages

• Build with regulatory compliance in mind, including data protection and financial-sector requirements

• Work closely with architecture teams throughout the design and delivery process, from concept to implementation

• Turn complex security requirements into clean, maintainable code

• Uphold strong testing standards, particularly for security-critical functionality

• Bachelor's degree in Information Technology, Computer Science, Business Administration, Engineering, or a related field
• 5+ years of hands-on Java development (newer versions)
• Deep expertise in Spring Boot application development and auto-configuration
• Hands-on experience implementing JWT-based stateless authentication, OAuth 2.1 / OIDC resource server configuration, filter chains, and method-level security
• Practical experience writing aspects for cross-cutting concerns (authorization, auditing, masking)
• Understanding of aggregates, domain services, repositories, and the importance of keeping domain objects free of infrastructure concerns
• Experience in Spring Data Redis / Lettuce
• Experience in JUnit 5, Mockito, Spring Boot Test or Test containers
• Experience deploying stateless Spring Boot services on Kubernetes

Nice to have:

• Experience with Open Policy Agent (OPA) or Drools BRMS

• Familiarity with HashiCorp Vault and spring-vault-core
• Knowledge of GDPR, DORA, or PSD2 in a technical context
• Entra ID / Azure AD OIDC integration experience
• Experience in core banking or financial services platforms
• API Gateway (policy enforcement, coarse-grained AuthZ)

• An attractive salary package
• Private health insurance plan
• Career development and growth opportunities
• Continuous training via personalized seminars
• An amazing private & open-office workspace in Athens #LI_Hybrid
• Flexibility to a remote work model as well
• Stable and enjoyable working environment