Back-end Developer

Cosmote Global Solutions Nv

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Brussels, Brussels, Belgium on site Until 8/21/2026 First posted February 26, 2026 Last posted February 26, 2026
Job description

COSMOTE Global Solutions NV is at the forefront of the ICT industry as a trusted member of the OTE Group of Companies, dedicated to delivering comprehensive ICT Solutions and Services. We are looking for a talented Back-end Developer to enhance our team.

As a Back-end Developer, you will play a critical role in designing scalable applications to meet the evolving needs of our clients. Your expertise will ensure the smooth integration of server-side logic with front-end components, enabling our applications to function seamlessly and efficiently.

Key Responsibilities:

    • Development of back-end website applications.
    • Integration of user-facing elements developed by a front-end developer with server side logic.
    • Implement core business logic.
    • Creation of servers and databases for functionality.
    • Design and implementation of data storage solutions.
    • Understanding and implementation of security and data protection.
    • Optimization of the application for maximum speed and scalability.
    • Design and develop APIs.
    • Participating in the design and creation of scalable software.
    • Taking lead on projects, as needed.
    • Maintenance of code integrity and organisation.
    • Writing clean, functional code on the back-end.
    • Compile and analyse data, processes, and codes to troubleshoot problems and identify areas for improvement.
    • Testing and fixing bugs or other coding issues
    • Meet both technical and consumer needs.
    • Write technical documentation

Requirements

    • Bachelor’s Degree in IT or a related field
    • At least 17 years of experience in IT
    • At least one year of expertise in back end:  Vert.x, Kotlin , Java (> 17) , Spring Boot (WebFlux), Hibernate.
    • At least one year of expertise in Architecture & Integration: Microservices Architecture, API-driven Development, AS4.
    • At least one year of expertise in Database: MongoDB , PostgreSQL, Virtuoso Triple Store, OpenSearch
    • At least one year of expertise in Containerization & Orchestration: Docker, Kubernetes
    • At least one year of expertise in Security: OpenID Connect, OAuth2, TLS, Keycloak
    • At least one year of expertise in Security Testing & Dependency Management: SAST, DAST, Fortify, SonarQube, Sonatype, Dependency-Track, Maven
    • At least one year of expertise in Collaboration & Productivity Tools: JIRA, Confluence, Office 365, SharePoint
About this role

Summary

Designs scalable backend applications, integrates APIs, maintains security, and optimizes for speed.

Job title

Back-end Developer

Experience level

17+ years

Industry

ict

Location requirements

Brussels, Belgium, on-site work required.

Salary

Not specified

Management role

No

Skills & keywords

Required skills

kotlinjava > 17spring bootmongodbdockerkubernetesopenid connectoauth2tlskeycloaksastdastsonarquellesonatypemaven

Preferred skills

None specified

Specializations

backendapimicroservicessecuritydocker
Locations

Structured locations inferred from the posting.

Brussels, Belgium

On-site City