Senior Web Developer - PHP/Symfony - ASAP Start - Freelance / CDI

A major player in public mobility and sustainable development in Belgium is currently expanding its Embedded Systems Department. This department is responsible for developing a new onboard computer for a fleet of over 3,500 vehicles, as well as an Operational Support System (OSS) that provides real-time operational data to internal business units. As part of this initiative, the organization is seeking a skilled professional to contribute to the continuous evolution and rollout of this platform across various departments.

To support the ongoing optimization of a web-based operational platform, we are looking for a Front-End Web Expert. The ideal candidate will bring deep expertise in improving code quality, enhancing front-end performance, and introducing modern development practices – particularly in real-time systems (e.g., Mercure), REST API architecture, and automated testing frameworks.

• Mentor and support a team of web developers
  
  

• Optimize front-end (React/TypeScript) and back-end (PHP/Symfony/API Platform) performance
  
  

• Improve resource efficiency (memory, CPU usage, initial load times)
  
  

• Define and implement front-end coding standards (naming conventions, error handling, etc.)
  
  

• Refactor and modernize the React/TypeScript codebase according to best practices
  
  

• Gradually replace legacy code (e.g., Bootstrap, outdated JavaScript, older React versions)
  
  

• Establish a structured, scalable front-end development framework (conventions, modular organization, quality benchmarks)
  
  

• Strengthen API structure and security using API Platform
  
  

• Provide ad-hoc technical leadership (code reviews, testing practices)
  
  

• Stay up to date with front-end technologies and continuously propose improvements
  
  
  
  

TECH STACK

• Back-end: PHP 8+, Symfony 6 (LTS), API Platform, Mercure, MariaDB, Istio, ELK, Azure, Node.js
  
  

• Front-end: TypeScript, React (with MUI)
  
  

• Queueing: RabbitMQ
  
  

• Testing: Playwright (E2E), PHPUnit, JEST
  
  

• Databases: MariaDB
  
  

• Caching: Redis
  
  

• CI/CD: Azure DevOps, Docker, Git, Kubernetes
  
  

• Monitoring: APM (Kibana), Grafana, PMM, RUM (Kibana), Loki, OpenTelemetry
  
  

• In Progress: Migration to React / TypeScript / API Platform