We are looking for a senior backend engineer to help rebuild a mission-critical system used in live operational environments. You join a multidisciplinary engineering team working on high-impact, real-time software that integrates large volumes of data across multiple components.

You work from an existing legacy application (VB.NET) and incrementally redesign and implement a new backend in PHP 8+ using Laravel and Slim. You combine strong backend expertise with a deep understanding of API-first design, data processing and integration patterns. You take ownership of complex problems, help shape technical decisions and support colleagues through reviews, pair programming and knowledge sharing.

What You Will Do

• You build and maintain scalable backend services in PHP/TypeScript and deliver clean, testable code that follows best practices.
• You translate functional analysis into technical solutions, work with RESTful APIs and messaging systems, and participate in designing prototypes for new features.
• You collaborate closely with product management, functional analysis, hardware teams, ML teams and external integrators to deliver high-quality software.
• You participate in co-creation workshops, integrate with external systems and ensure robust communication between services.
• Code reviews, unit testing, and continuous refactoring are part of your daily work.
• You combine complex multi-indexed datasets using graph/vector-based approaches and ensure data pipelines are reliable.
• You support QA by validating your own work end-to-end and contribute to shaping CICD guardrails together with DevSecOps (without owning DevSecOps delivery).
  

What are we looking for?

• 7+ years’ experience in backend development
• Strong expertise in PHP 8+, Laravel, Slim (or similar microframeworks like Lumen/Silex)
• Solid experience with JavaScript/TypeScript on the frontend (Vue.js preferred)
• Experience working from and interpreting legacy VB.NET logic
• Deep experience with PostgreSQL and solid SQL skills
• Strong knowledge of Linux environments and shell scripting
• Experience with RESTful APIs, OAuth2, JWT
• Experience with message brokers (Kafka, RabbitMQ)
• Solid understanding of secure coding practices
• Experience with Git, GitLab or GitHub
• Experience with code quality tooling (e.g. SonarQube)
• Experience in Agile teams (Scrum/Kanban)
• Language: Dutch OR French (fluent), English (reading level)
  

Nice-to-Have Skills

• Experience with NoSQL systems (MongoDB)
• Experience with document-oriented search (OpenSearch, ELK)
• Basic knowledge of orchestration (OpenShift, Nutanix, HashiCorp)
• Experience with modelling/simulation/test-load generation in lab environments
• GraphQL exposure
• Experience generating automated documentation (OpenAPI/Swagger, etc.)
  

What do we offer?

Location: Brussels (hybrid, min. 2 days/week on-site)

Contract: Freelance 

Start: 15 December 2025

End: 31 December 2025 - extension possible