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Mobile Developer

3-5 jaar

Joyn, you're saying?

Yes, Joyn, a digital loyalty application that aims to create a unique neighbourhood by centralizing rewards and experiences. Joyn’s digital loyalty program offers local merchants tools to stay in touch with their customers. Our mission is to strengthen the local commercial heart in cities because we believe that local shopping is worth gold! Today we already count 7,500 affiliated stores across Belgium with more than 2.0 million users.

Are you our new Mobile Developer?

Take you chance:

As a Joyn Mobile Developer, you will be part of the Joyn R&D team that delivers added value to the Joyn Product by developing and maintaining software services and applications. 
In particular, you will be responsible for developing, maintaining and elaborating Joyn’s merchant and user mobile touchpoints with a focus on quality. You’ll work on and write code for applications that are part of the bigger Joyn transactional platform, which handles approximately 80,000 transactions a day on average.

You will:

  • primarily build and working on mobile applications and spend a good chunk of your time coding - and code-reviewing others to ensure we maintain a high standard of quality. The specific code depends on the mobile platform. Currently, it’s Java for Android and Swift for iOS.
  • participate in design and code reviews, develop, debug, or modify source code and unit tests. As a result you will build well designed, clean applications with solid technical foundations.
  • help out and deliver across the entire app life cycle –concept, design, build, deploy, test, release to app stores and support.
  • work closely with our product management team, QA, and operations team to build reliable products for our merchants and users.
  • work closely with the other developers and the Product Owner in a high performing agile team. You’ll collaborate with fellow Mobile Developers to solve problems as they arise.
  • report status to the Product Owner and Technical Lead and identify issues and risks proactively.
  • be responsible for upholding yourself and those around you to the highest coding standards including unit testing code for robustness, usability and reliability. Usability and Quality are two of our fundamental engineering values.
  • be using active listening and communication skills to understand what merchants and users are looking for in their mobile app.
  • work in a small, fast-moving team with lots of responsibility (and few roadblocks to getting things done).

Who are we looking for?

Soft skills

  • You are a real team player but you’re also able to work independently.
  • You’re feeling comfortable with collaboration, open communication and reaching across functional borders.
  • You understand the importance of the end-user and an end user’s mobile needs.
  • You’ve good listening and interpersonal skills.
  • You’re eager to learn and able to work result-oriented.
  • You have excellent analytical skills with a good problem-solving attitude.
  • You like working in the flexible and agile environment of an emerging scale-up.

Hard skills

  • 2 to 5 years of experience in iOS and Android development resulting in proven compelling mobile device specific user interfaces and experiences
  • Wide knowledge of computer science and/or software engineering – through a related degree or diploma, but we also recognize practical experience. Expertise in standard architectural patterns (e.g. Service Oriented Architecture) & best practices, and concepts in computer science
  • Interested in modern (i.e. non-typical enterprise) way of developing application stacks
  • Build prototypes at tech scoping stage of projects
  • Agile development knowledge (Scrum, Kanban)
  • Experience integrating RESTful web services
  • Experience in writing unit and integration tests
  • Interest (or skill) in UX design and/or identify UX issues
  • Functional programming skills and/or interest 
  • Keep up to date on the latest industry trends in mobile technologies
  • Familiar with the Atlassian toolset: JIRA, Confluence and BitBucket is a plus
  • Previous experience in the financial/transactional world is a plus
  • Languages:

                            Dutch: Fluent
                            English: Fluent
                            French: Nice to have

Technical skills


  • Strong OO design and programming skills in Objective-C and more preferably Swift
  • Familiar with iOS design patterns such as MVC, MVVM and Coordinator
  • Familiar with iOS SDK (UIKit, Cocoa Touch, Core Data, Core Location, etc) 
  • 3rd party frameworks: Cocoapods (dependency management), KingFisher (image handling), Alamofire HTTP networking
  • IntelliJ AppCode and xCode 8


  • Strong OO design and programming skills in Java (J2EE/ J2ME) 
  • Familiar with the Android SDK and RxJava/RxAndroid 
  • Familiar with Gradle and Product Flavors
  • 3rd party frameworks: Dagger 2, Retrofit 2, ButterKnife, OkHttp3 HTTP/2 networking

  • Good experience consuming JSON/REST web services from a mobile application
  • Knowledge of PostgreSQL, MySQL or similar database management system 
  • Fabric for crash reporting or similar (New Relic)
  • Experience with Firebase Cloud Messaging (or other Push Notification frameworks)
  • Familiar with app deep linking and OAuth 2.0
  • Testing: JUnit, Mockito, Espresso, ...
  • Release management: Play Store and iTunesConnect
  • Excited to experiment and work with new technologies like Kotlin and React Native
  • Proficient understanding of Git
  • Plus:
          Experience using social media APIs
          Experience with Play Store / App Store app marketing and Analytics
          Experience with Continuous Delivery/Integration
          Experience with Test Automation
          Experience with Microservices and AWS

What’s in it for you?

You will be working mainly in our office in Hasselt; Corda Campus.

  • Competitive salary package
  • Full time, 5 days a week
  • mealvouchers
  • ecovouchers
  • Smartphone + subscription
  • 12 extra vacation days
  • Hospitalization insurance
  • Great colleagues
  • Good work environment


Send an e-mail with your application (CV and motivation letter) to

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