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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!

    Pros and cons

    • You regularly participate in brainstorm sessions about user experience, data, and task flow with the UX Designer, Product Owner, and Data Scientists in your team.
    • You create disconnected, highly congruent, and testable code that can easily be maintained and is future-proof.
    • You coach our Developers and provide them with feedback.
    • You and the development team make sure all systems run perfectly behind the scenes.
    • During team outings, you will most likely eat pizza.


    It's "new Sprint"-day, and a new sprint means getting started on a new user story: a new store is opening, and needs to be configured in your application. You double check the story in JIRA, and it looks like there are some nice clean Acceptance Criteria for you to write your tests against! You double check the last few points with a colleague, and then stick your headphones on and focus for a while.

    During lunch, you take a walk around Rotterdam with colleagues from your team, but you make sure to return in time for a backlog refinement meeting and a demo of another team that you work closely with. After these two sessions, you help a colleague who's a bit stuck with the next step in their Red-Green-Refactor cycle. Just when you've finished pairing, a key stakeholder walks past the team space and invites you to a friendly game of ping-pong while you answer some questions that came out of your recorded demo.

    Before heading off, you create a Pull Request in the application GitHub repo with the new store configuration you were working on in the morning; tests run in TeamCity, and it's green! You're confident in your tests, but you still need a colleague to double-check your PR, so that'll wait for the morning now. You always try to head out in time to catch your train, but yet again, you're cutting it fine, because Rotterdam Centraal is just over the road. Doei!

    Your specifications

    • You have at least 6 years of experience as a C# Developer.
    • You have experience with software architecture and building .NET applications.
    • You have experience with Web API or MVC in .NET Core.
    • You're able to solve problems by using accepted best practices and principles, such as TDD/BDD, SOLID, and design patterns.
    • You have experience with various types of data stores, such as Oracle or Dynamo/Cosmos.
    • You know how Git works (and GitHub).
    • Working with Scrum/Agile working is second nature to you.
    • Having experience with front-end development (React), Javascript, HTML5, and CSS is a plus.
    • It's even better if you're able to automate and implement recurring tasks in a CI/CD system.
    • You're fluent in English.

    Included by default


    • Money.
    • 25 leave days. As long as you promise to come back.
    • Travel allowance and a retirement plan.
    • Relocation assistance, from A to Z (if you live abroad).
    • With over 30 training courses in our own Coolblue University, you can become a little better every day.
    • An international working environment. With colleagues from places like Belgium, Spain, Australia, Mexico, and Italy.
    • Room for new initiatives and ideas. We're always open to those. Doesn't matter if you've worked with us for a week, a month, or a year.
    • A horizontal organisation in the broadest sense. You could just go and have a drink with the boss.
    • A discount on all our products.
    • A picture-perfect office at a great location. You could crawl to work from Rotterdam Central Station. Though we recommend just walking for 2 minutes.
    • Extraordinarily good work environment, including freshly made snacks, monthly drinks, legendary Coolblue parties, awesome team activities.


    Questions about Software development vacancies?

    Questions about Software development vacancies?

    Funda Funda Ozcelik Karaagac

    Application process

    1. Apply
    You've applied? Awesome. We'll get back to you as soon as possible.
    2. Introductory call and test
    One of our Recruiters will call you for a preliminary chat and give you a small technical assignment.
    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

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