Back End Developer

Security-Focused Backend Engineer

Brussels, Belgium

Hybrid 2 days on-site, 3 days work from home

Up to €420/day

12 months contract - possibility of extension

Are you a back-end engineer with a passion for cybersecurity and secure system integration?

This is your chance to make an impact on high-level international projects!

We're looking for a Secure Data and Document Expert to join one of our public sector clients in Brussels. You'll contribute to essential digital transformation initiatives that prioritise data confidentiality, integrity, and secure interoperability.

Your Role:

In this role, you'll act as the go-to expert for secure data exchange, ensuring that critical messaging systems meet the highest security standards. Key responsibilities include:

• Designing and implementing secure integration layers between backend systems and messaging software
• Advising on all aspects of secure data transmission: confidentiality, integrity, authentication, and availability
• Conducting security assessments and supporting vulnerability testing
• Maintaining and optimising transport/messaging protocol specifications
• Collaborating with cross-functional teams to guide integration strategy and technical documentation

Your Qualifications:

• A Master's degree with 5+ years (or Bachelor's with 9+ years) of experience in secure document exchange and protection
• Strong knowledge of digital signatures, PKI, ASiC, X.509, and eIDAS compliance
• Deep expertise with secure messaging and transfer protocols such as ebMS3, AS4, XML, JSON, and BDXL
• Backend development proficiency in Java with strong knowledge of OOP, SQL databases, and transactional consistency (ACID/XA)
• 3+ years of mobile development experience on both Android (Java/Kotlin) and iOS (Swift)
• Familiarity with CI/CD pipelines and observability tools (Jenkins, Git, SonarQube, Selenium, JMeter, Dynatrace, Splunk)
• Experience with containers and infrastructure: Docker, Kubernetes, Linux, TPM, HSM
• Fluency in English and French (C1 level), with strong communication and documentation skills

Bonus Points For:

• Experience with EU institutions
• SANS Web Application Tester certification
• Familiarity with TPM/HSM-based cryptographic hardware
• Agile project delivery using SCRUM or OpenPM2
• Certifications in cybersecurity, project management, or software development

5V Tech are acting as an Agency for the purposes of this contract. We offer a reward scheme if you can recommend someone for this contract, up to €250 for you and an additional €250 to a charity of your choice. 5V Tech are recognised talent solutions experts within IoT and Deep Tech working across Europe, the UK and North America.