Senior PHP Full Stack Engineer

You join a multidisciplinary engineering team working on next-generation systems that support real-time intelligence, operational decision-making, and national-scale data processing. You help rebuild a critical legacy platform from VB.NET into a clean, modular PHP application while contributing to complex data logic, hit-generation engines, and integrations across the police technology ecosystem.You start from an existing VB.NET application, reverse-engineer the logic, and translate it into a modern PHP8+ codebase using Slim and Laravel. You build new components, integrate multi-indexed and graph-based data sources, and apply an API-first approach for all new development. You design, code, test, and review your own work, contributing to continuous improvement and maintainability.You collaborate with product managers, analysts, hardware and AI/ML teams, and external integrators. You participate in pair programming, review contributions from colleagues, and ensure code meets quality, performance and security expectations.Key responsibilitiesUnderstand and refactor logic from a VB.NET legacy application into a modern PHP8+ architectureBuild clean, secure back-end components using Slim, Laravel or similar microframeworksCombine and process multi-indexed datasets using vector or graph-based logicWork API-first, design and consume REST interfaces and (optionally) GraphQLApply test-driven development and ensure high testability for all new codeDeliver full end-to-end features, including QA of your own workCollaborate with multidisciplinary teams including hardware, data, AI/ML and UXPerform pair programming and code reviews to maintain shared code qualityContribute to documentation, continuous improvement and engineering standardsWork with external vendors whose codebases may not be internally accessibleWhat are we looking for?Bachelor’s degree in Engineering, Computer Science or equivalent experience10+ years of full-stack engineering experienceStrong experience in PHP, including Slim, Laravel, Symfony or equivalent microframeworksAbility to read and understand VB6/VB.NET for legacy migrationSolid knowledge of JavaScript frameworks (Vue.js preferred)Experience with version control (Git, GitLab/GitHub)Strong expertise with PostgreSQL, and familiarity with other SQL/NoSQL enginesExperience with OpenSearch or ELK is highly valuedStrong knowledge of Linux and shell scriptingExperience with Kafka, RabbitMQ or similar queueing/brokering technologiesSecurity best practices, including JWT, OAuth2 and secure-by-design codingExperience with SonarQube or similar code quality toolingKnowledge of REST API design; GraphQL is a plusExperience with Agile delivery, JIRA/ConfluenceDutch or French as native language, with passive knowledge of the other; reading knowledge of EnglishWhat do we offer?Start date: 1 December 2025Duration: Until end 2025 (extensions expected)Workload: FreelanceLocation: Brussels (min. 2 days/week on-site)