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Apollo Solutions

Java Consultant

Apollo Solutions
Belgium · Contract · Mid-Senior

We are supporting a leading telecommunications provider on several business-critical digital initiatives, including large-scale platform modernization and customer-facing system evolution. We are looking for an experienced Backend Java Developer with a solid understanding of frontend technologies to join a modern, modular engineering environment.


Logistics

  • Role: Freelance Backend Java Developer
  • Contract: 12–24 months
  • Location: Brussels (Hybrid - 2 days/week on-site)
  • Languages: English + French or Dutch
  • Start Date: ASAP / January
  • Rate: Competitive & negotiable


Responsibilities

  • Design, develop, and maintain scalable backend services using Java and Spring Boot
  • Contribute to greenfield initiatives and long-term platform evolution projects
  • Translate complex business and operational requirements into robust technical solutions
  • Apply clean code, TDD, and collaborative development practices (pair programming)
  • Support and evolve system architecture using DDD and hexagonal architecture
  • Build and maintain solutions within CI/CD pipelines and containerized environments
  • Participate actively in code reviews and agile ceremonies
  • Collaborate with frontend teams when required to ensure end-to-end solution quality
  • Work on high-throughput, highly available systems typical of telecom environments


Required Skills

  • 6+ years of experience as a Backend Java Developer
  • Strong expertise with Spring Boot
  • Experience with Kafka or other event-driven / messaging systems
  • Solid knowledge of REST APIs and relational databases (Oracle, PostgreSQL, or similar)
  • Experience with Docker and Kubernetes
  • Familiarity with CI/CD tooling (Git, GitLab, Jenkins, SonarQube)
  • Working knowledge of frontend technologies (Angular, React, TypeScript)
  • Comfortable working autonomously within Agile/Scrum teams
  • Experience working on large-scale, distributed systems


Nice to Have

  • Experience in the telecommunications industry (BSS/OSS, billing, provisioning, network-related systems)
  • Exposure to legacy system modernization or modularization initiatives
  • Knowledge of DevSecOps or security-by-design principles
  • Experience working in Spotify-model or squad-based organizations
  • Familiarity with high-availability, low-latency systems


Interested? Get in touch to discuss details and next steps.

Key Skills

Ranked by relevance

java postgresql jenkins oracle gitlab git
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Posted
Jan 13, 2026
Type
Contract
Level
Mid-Senior
Location
Brussels

Industries

Telecommunications

Categories

Information Technology

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