Software Development Engineer - Backend - Security - Login (f/m/d)

The Login team is the pillar of the Decathlon ecosystem. Composed of passionate and multicultural profiles, our team of about ten people builds a secure and high-performance authentication solution for over 80 countries. Our ambition? To offer a fluid member experience through a single, highly secure entry point. Our current challenge is significant: to lead an international architecture migration from our Spring Security 5 system to Spring Security 7. Join a team of passionate individuals at the heart of Decathlon's global challenges!

YOUR FUTURE CONTRIBUTION

The main mission is to support the creation of new features and the improvement of the application, all within an agile organization to deliver maximum value to our products quickly and frequently.

DevSecOps Context: you build it, you run it, you enjoy it!

• Security by Design

OAuth 2.1 / OIDC Standard: Contribute to the implementation of these protocols to ensure secure access to our services.

Code Security: Apply security principles from the design phase (OWASP, protection against injections, secure session lifecycle management).

Security Watch: Proactively identify and fix potential vulnerabilities within the Java/Spring ecosystem.

Cloudflare Administration: Manage, configure, and optimize our Cloudflare infrastructure (WAF, DDoS protection, DNS, CDN, Bot Management).

Audit and Monitoring: Implement threat monitoring, analyze security logs, and react to incidents (SOC/SIEM).

• Development & Delivery

Production: Ensure delivery on the core CIAM components (authentication engines, token management, protocol integrations).

Advanced Patterns: Implement resilient solutions based on Kafka (CDC & Outbox Patterns) to ensure data consistency without compromising performance.

Integrated Quality: Guarantee stability through rigorous automated tests (Playwright, Gatling) from the development phase.

•   Data-Driven Approach: Tracking & A/B Testing

Experimentation: Implement A/B testing strategies via Statsig to validate authentication tunnel evolutions in a granular manner.

Behavioral Tracking: Integrate and maintain accurate tracking via Amplitude to analyze user journeys and identify friction points.

Product Performance: Collaborate with Product teams to translate business needs into measurable and scalable technical implementations.

• Architecture, Scale & Observability

System Design: Model complex flows using the C4 Model to ensure a clear vision of interactions between services.

Infrastructure & Ops: Deploy and operate your services on Kubernetes (Helm), with complete mastery of observability via Datadog.

WHAT YOU BRING

• +7 years in Java in high-traffic distributed environments.
• Security Expertise:
• OAuth 2.1 / OIDC Standard
• Experience with Keycloak or equivalent
• Code Security (OWASP, injections, secure sessions)
• Spring & Spring Security: Knowledge of internal mechanisms (Filters, Authentication Providers, etc.).
• Event-Driven Architecture: Experience with Kafka, CDC, and use of the Outbox pattern.
• Data & Growth: Experience with tracking tools (Amplitude) and Feature Flagging / A/B testing tools (Statsig).
• Cloud & Tools: Kubernetes, Helm, Datadog.
• Testing: Playwright (E2E) and Gatling/Blazemeter (Load testing).
• Language: Technical English (documentation is mandatory).

WHAT WE OFFER YOU

Hybrid work organization;

Equipment provided in line with your missions and our societal commitments (Mac or Windows);

A local project team within a global network (possibility of international career);

Skills development and support (diversity of projects, internal and external training, etc.);

Remuneration package (employee share ownership, monthly/quarterly bonuses).

OUR COMMITMENT TO INCLUSION AND ACCESSIBILITY

At Decathlon, we recognize the immense value that diversity brings to our teams and we continuously strive to foster and cultivate an inclusive and equitable workplace: that's why Inclusion is one of our Human Fundamentals. We encourage individuals from all backgrounds and abilities to apply, as we are convinced that diversity of thought, culture, identity, and lived experience makes us stronger.

Decathlon is also committed to providing an inclusive and accessible selection process for all candidates. If accommodation is needed, you can request it via the application form; this request will be confidential. These requests do not affect the outcome of the recruitment process.