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Senior C# Developer

As a Senior C# Developer, you'll build modern applications for the Coolblue back office. We have a lot of friends, and they crave well-structured data and user-friendly, task-focused applications. We need your help to make them smile!

    What you tell people at parties

    “I'm kind of a writer. But I write in a very special language."

    What you really do

    • You develop intuitive applications that connect to our web services.

    • You develop small, well-crafted services that extract responsibilities of the current back office application, essentially creating a service-oriented architecture for our new applications.

    • You have regular brainstorms with your team's UX-designer and Product Owner about user experience, data, and task flow.

    • You write testable code that will be continuously integrated and deployed, and will therefore have a real effect on live environments.

    • You coach and provide feedback to other developers.

    How you do it

    • You actively participate in your multidisciplinary team’s Scrum process.

    • You gather from end users and developers. After evaluation of this feedback you might incorporate it in a new iteration.

    • You initiate and participate in discussions about technical choices, architecture, tools and processes. Choices that were made in the past are not rules.

    • You open pull requests and discuss solutions with your teammates to make your team even better.

    • You perform code-reviews in order to provide feedback that makes your team even better, and to maintain a high level of quality in our code base.

    • You help improve the overall software quality by writing SOLID and testable C# code.


    You'll work in a team with other Sharp Developers, each of them with their own fanaticism, ranging from code quality and testability, to algorithms and scalability. Together with the team next door forms, your team forms a family that is supported by a Team Lead, and complemented by a Scrum Master, a Product Owner, and a UX-designer.

    A day at the office

    Yesterday, you and your teammates demoed the work of the previous sprint to the end users. The (web) application is showing some serious advantages over the current way of working, and is looking pretty slick. You conclude that  the end result was good, but things could've gone a little better.

    It’s the beginning of the new sprint and you assign the next top priority user story to yourself: implementing a new RESTful endpoint. You take a break for lunch at the Markthal with your newest friends; making sure that you’re back in time for a meeting with the users. You stop on the way back to grab another coffee and help a fellow colleague who is having problems implementing a unit test. You spend the remainder of the day working on your user story; you just need to finish up the test cases and push it into CI. You grab your headphones and get on with it. Whew, done! Time for some Friday drinks.

    What we're asking

    • You’re smart and you have some way to prove it.

    • You have a minimum of 6 years experience as a C# Developer.

    • You’re experienced with architecting and building .NET applications.

    • You have experience with Web API.

    • A nice plus if you have experience with frontend development with .NET Core, ASP.NET MVC, Javascript, HTML5 and CSS.

    • You have experience with different types of data stores, such as Oracle or RavenDB.

    • You have a solid understanding of Git (and GitHub).

    • Scrum/Agile comes naturally to you.

    • You're able to solve problems using accepted best practices and principles like TDD/BDD, SOLID and design patterns.

    • You care about code quality.

    • You know how to automate recurring development steps and implement them in continuous integration and deployment systems.

    What we're offering

    • Money.

    • Over 30 training courses at our own Coolblue University.

    • A 10% discount on all of our products.

    • An awesome workplace. With freshly prepared meals, monthly TGIF drinks, epic Coolblue parties,team activities, and an informal, playful office space.

    • 25 leave days. As long as you'll promise to come back.

    • Travel allowance and a pension plan.

    • An office at the best possible location. It's only a short stumble away from Rotterdam Central Station. Or a 2-minute walk.

    • Relocation assistance, from A to Z (if you live abroad).

    • Dutch language courses. To help you become a Rotterdammert.

    • An international work environment. With colleagues from places like Belgium, Spain, Australia, Mexico, and Italy.

    • Parties. All-night LAN.

    Questions about Software development vacancies?

    Questions about Software development vacancies?

    Martijn van Citteren

    Application process

    1. Apply
    You've applied? Awesome. We'll get back to you as soon as possible.
    2. Introductory call
    One of our Recruiters will call you for a preliminary chat.
    3. First interview
    A Recruiter and a Developer will call you for a Skype interview to get to know you better and to answer any questions you might have.
    4. Meet & Greet
    If you live outside NL we'll fly you in to meet us, so we can show you your future workplace.
    5. Offer
    We'll make you an offer you can't refuse.
    6. Hired
    Just sign here, here, and here. Booyah! You're hired.

    Apply for this job

    Apply now if you're interested in this vacancy! Make sure you have the following documents ready to add to your application.

    • CV
    • Cover letter

    Thanks for your application

    Your application is sent!