Android Software Engineer

Our team Digital Sports is looking for an Android Software Engineer based in Lille.

Our purpose: "Bring people together through sport to make wellbeing accessible for all."
At Decathlon, our ambition is clear: to bring people together through sport and make wellbeing accessible to the greatest number.
To bring this goal to life, we rely on two major strengths:

• Our teammates, who are the beating heart of our ecosystem.
• Our local roots, which connect us to each sports community to offer unique solutions (products, services, and experiences).

To propel this vision, Digital is a key lever.

Your future playground: the Digital Sport Unit
A true link between our sports brands and digital, this team designs the solutions of tomorrow.
By joining us, you will have a direct impact: you will contribute to creating and deploying digital products, services, and experiences to simplify the daily lives of our teammates and delight our sports users' practice.

The Connected Locker is the software core that bridges all our physical products (bikes, treadmills, watches) and Decathlon's digital ecosystem.

Your challenge? Absorb complexity. Each product has its own protocols and hardware specificities; the CL's role is to unify all of this into a modular and robust library so that application developers (Decathlon HUB, Mobility..) can integrate any equipment with a few lines of code.

YOUR MISSIONS

• Modular Architecture & SDK Design: Design and evolve a decoupled and scalable Kotlin architecture, allowing new product types to be added without rewriting the core of the system.

• Hybrid Connectivity & IoT: Master the Bluetooth Low Energy (BLE) stack on Android (lifecycle management, scans, reconnections, manufacturer/ROM specificities) for local communication, and MQTT/REST for Cloud communication

• Development of a "Test App": 

  • Develop and maintain a dedicated test application (Jetpack Compose).

  • Allow QA to validate SDK functionalities in isolation.

  • Integrate simulation tools (mocking) to test hardware error cases that are difficult to reproduce in real life 

• Abstraction (The Art of Android SDK): Create simple and idiomatic public APIs (Kotlin Coroutines / Flow) to mask the complexity of hardware state machines from user applications.

TECHNICAL STACK

• • Language: Kotlin (100%)

  • Asynchronism: Coroutines, StateFlow / SharedFlow

  • Connectivity / IoT: Android BLE Stack, MQTT (e.g., Paho/HiveMQ), AWS IoT Core, REST / WebSockets

  • UI (Test App): Jetpack Compose

  • Architecture & Injection: Clean Architecture, Dependency Injection (Hilt / Koin)

  • Tooling / CI-CD: Gradle (Build Logic / Version Catalogs), Git, CI/CD pipelines for SDK/AAR publication.

WHAT YOU NEED TO SUCCEED

• You are a Kotlin / Android expert with a real "Platform / SDK" vision (you think reusable library/AAR before thinking screen/UI).
• You master BLE on Android and know its pitfalls (permissions, background restrictions, variations across OS versions/manufacturers), and you are comfortable with real-time network protocols (MQTT).
• You have solid experience in software architecture (Design Patterns, Modularity, Dependency Injection).
• You are based in Lille, ready to test your code on sports machines 50m from your office.
• A strong appetite for teamwork and a culture of sharing.
• An interest in the impact of sport on personal and collective development.
• The desire to join a company committed to Tech4Good and responsible innovation.

WHY JOIN US?

At Decathlon, we make it a point of honor to offer a fulfilling and motivating work environment.

• Hybrid work organization (2 days of remote work per week);
• Equipment provided in line with your missions and our societal commitments (Mac, Windows, or Chromebooks);
• A local project team within a global network (possibility of international career);
• Skills development and support (diversity of projects, technical certifications from the first year, internal and external training, etc.);
• Remuneration package (employee participation in company actions, monthly/quarterly bonuses).

🚀 A stimulating work environment: company certified Great Place to Work and Happy Trainees.
💰 Attractive benefits (after 3 months of seniority):

• Monthly bonuses, profit-sharing, shareholding
• CSE benefits
• 25% discount on our products
• 50% reimbursement of transport pass & urban mobility assistance
  🎯 Tailored support: coaching, internal and external training, knowledge sharing.
  ⚡ A culture of sport and product testing: become an ambassador for our innovations and join our internal sports teams!

I don't know the sports industry, do I have a place at Decathlon?

Of course! We are looking for passionate and motivated people above all, whether in their field of expertise or in sport in general.