Senior Java Software Developer Engineer - Freelance (M/F)

About the role

Taux journalier (TJM): 540€/day CONTEXT At the heart of the CRM subdomain, the team designs and operates the global customer engagement platform. We develop technological solutions enabling our global and local marketing teams to orchestrate and distribute personalized, engaging, timely, and responsible product and service recommendations. Our team designs and operates the automation and hyper-personalization platform, deployed in over 70 countries. Our ambition for 2026-2027? To move from a proactive CRM model to a predictive and omnichannel model (WhatsApp, RCS, Push, Email). TECHNICAL STACK * Languages & Frameworks : Java 25, Spring Boot * Data & Messaging : PostgreSQL, Redis, Apache Kafka, BigTable * Cloud & Infra : Google Cloud Platform (GCP), Kubernetes, Docker, Terraform, Git/GitHub (GitOps), Github Actions, Datadog, APIM (Gravitee) * Collaboration : Slack, Jira, Confluence, Google Workspace OBJECTIVES AND DELIVERABLES As a technical pillar of the team, you will shape the CRM offering of tomorrow and support the collective toward excellence: * Technical Guidance & Architecture : You define the technical trajectory, make critical architectural decisions, and solve high-availability challenges in close collaboration with the team and stakeholders. * Code Quality & Best Practices : You are responsible for writing clean, testable, and maintainable code (DDD, TDD), and you ensure rigorous code reviews. * Scalability & Resilience : You design systems capable of absorbing global load across multiple continents without ever sacrificing availability. * DevSecOps Culture : You actively participate in continuous deployment to production without interruption, in improving observability (alerting, monitoring), and in proactive incident management. * Leadership & Mentoring : You coach team members, encourage knowledge sharing, and carry the technical vision with generosity and authenticity. * On-call : The system is subject to 24/7 on-call duty. The frequency of on-call rotations is between every 3 and 6 weeks. WORKING CONDITIONS * On-site presence expected 3 days per week * Participation in 24/7 on-call rotations (on a weekly rotation basis) * Location : Lille * TJM : 540€ 1. Over 5 years of experience in software engineering with excellent mastery of Java 21 and the Spring / Spring Boot ecosystem 2. Solid experience in designing microservices, APIs, event streams (Kafka), databases (PostgreSQL), and caching (Redis) 3. Expertise in performance testing, establishing Service Level Objectives (SLO), and resolving complex incidents 4. Mastery of Infrastructure as Code (Terraform), Kubernetes, Cloud environment (GCP), and CI/CD pipelines 5. Excellent interpersonal skills, facilitator posture, strong team spirit, and a desire to help peers grow 6. Major assets : sensitivity to Front-end (JavaScript) and fine knowledge of the CRM/automation ecosystem