.NET / C# Developer

  • Brussels, Belgium
  • Full-Time
  • On-Site
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Job Description:

Mission Overview:

Join Keystone Solutions as a consultant for a .NET Developer with C# mission at our client. You will work within the client’s agile development teams to develop, extend, maintain, and monitor applications. As a Keystone Solutions consultant, you will collaborate closely with the client’s stakeholders, perform end-to-end responsibilities on-site, and contribute to both greenfield initiatives and application transformations.


Consultancy Model and Engagement:

As a Keystone Solutions consultant, you will operate within a consultancy framework, working primarily at the client’s location while leveraging Keystone’s community, coaching, and best practices. You will represent Keystone Solutions on-site, align with the client’s goals, and deliver measurable outcomes while benefitting from Keystone’s support network and knowledge-sharing culture.


Key Responsibilities:

  • You develop, extend, maintain and monitor applications within the domain.
  • You automate testing in all its forms in order to increase both code quality and application reliability, i.e., Unit-testing, integration testing, end-to-end testing, etc.
  • You write maintainable documentation for both existing software and new developments.
  • You collaborate with domain experts and business analysts in extracting requirements from user and business requests.
  • You participate in design discussions (high- and low-level) regarding application transformations as well as greenfield development.
  • You start initiatives to improve development processes, testing, operational management and infrastructure.
  • You try to reduce the amount of existing manual operational tasks as much as possible through automation.
  • You help set up inter-team communication channels for coordination regarding API changes, deployments, bugs, etc.

All of the above responsibilities will be executed as part of Keystone Solutions’ consultancy model, embedded with the client’s teams.


Experience:

  • You have at least 3 years of practical experience in C#.Net development
  • You have detailed knowledge of the .NET framework and surrounding ecosystem.
  • You have a strong foundation in OOP, in particular regarding C#.
  • You are acquinted with modern software design principles – i.e. SOLID, Gang of Four, event-driven systems, etc.
  • You have experience with ASP.NET WebApi and ASP.NET MVC.
  • You have experience with relational databases, preferably SQL server.
  • You have experience with CI pipelines, in particular Azure DevOps.
  • You are familiar with distributed system design and messaging technology.
  • Experience with .NET 10 is a plus.
  • Experience with NServiceBus is a plus.
  • Experience with Azure cloud platform is a plus
  • – i.e. App Services, Application Insights, Azure Key Vault, Azure Functions, ServicesBus, etc.
  • Experience with Docker is a plus.
  • Experience with React is a plus
  • Experience with Kubernetes is a plus


Education & Soft-Skills:

  • You have a Bachelor's degree - Computer Science, MIS or equivalent
  • You are fluent in both spoken and written English.
  • French speaking is a plus
  • You can work independently but are also a team player.
  • You are conscientious and act professional.
  • You are motivated and have a positive mindset.
  • You do not shy away from asking difficult questions.
  • You are Customer centric
  • You are Solutions Minded
  • You have abilities to learn quickly
  • You are organized
  • You have verbal and written communication skills
  • You have real-world experience with Agile development methodologies such as Scrum


Work Arrangement:

Home working: 2 days/week - On site 3 days/week (mandatory)


Consultancy Nature of Work:

As a Keystone Solutions consultant, you will integrate with the client’s teams, align with their delivery cadence, and work on-site for key activities such as design sessions, deployments, and stakeholder reviews—while leveraging Keystone’s internal community for peer support and knowledge exchange.


Dynamic Projects:

Keystone Solutions offers exposure to diverse client environments, enabling you to tackle varied challenges—ranging from greenfield services to complex application transformations—while maintaining continuity and stability within a single consultancy mission.


Turbo-Charged Learning and Development:

Benefit from broad learning experiences through mentorship, internal knowledge hubs, and peer sessions at Keystone Solutions, accelerating your expertise in .NET, cloud, DevOps, testing automation, distributed systems, and modern engineering practices.


Ambition Skyrocketing within a Consultancy Framework:

Grow your career through impactful client engagements. Keystone Solutions supports your professional goals with varied missions, increased responsibility, and opportunities to drive engineering improvements that matter.


Keystone Solutions Values in Action:

Being a K-Stone means bringing customer centricity, solution-minded thinking, professionalism, collaboration, and continuous learning to every client project. These values guide how we design, build, and deliver software as trusted consultants.


Role-Specific Impact as a Consultant:

In this .NET Developer with C# role, you will apply strong OOP foundations, modern design principles, and hands-on expertise with ASP.NET, Azure DevOps, and SQL Server across the client’s landscape. You will champion automation, reliability, and scalable architecture patterns within the client’s distributed systems, while fostering clear communication channels across teams.


How to Apply:

If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal.

Mission Overview:

Keystone Solutions is recruiting a .NET Developer with C# to join our consultancy team. This is a consultancy mission delivered at the client site through Keystone Solutions. You will work closely with our client, a key player in mobility offering more than 1000 parking lots across 9 European countries and serving 100 million annual customers, as they transform to become a more digitally oriented organization. As a Keystone Solutions consultant embedded within the client’s agile development teams, you will help design, build, and operate robust software that elevates customer experience at scale.


Key Responsibilities:

As a Keystone Solutions consultant working closely with the client, you will perform the following responsibilities under our consultancy model:

  • You develop, extend, maintain and monitor applications within the domain.
  • You automate testing in all its forms in order to increase both code quality and application reliability, i.e., Unit-testing, integration testing, end-to-end testing, etc.
  • You write maintainable documentation for both existing software and new developments.
  • You collaborate with domain experts and business analysts in extracting requirements from user and business requests.
  • You participate in design discussions (high- and low-level) regarding application transformations as well as greenfield development.
  • You start initiatives to improve development processes, testing, operational management and infrastructure.
  • You try to reduce the amount of existing manual operational tasks as much as possible through automation.
  • You help set up inter-team communication channels for coordination regarding API changes, deployments, bugs, etc.


Experience:

  • You have at least 3 years of practical experience in C#.Net development
  • You have detailed knowledge of the .NET framework and surrounding ecosystem.
  • You have a strong foundation in OOP, in particular regarding C#.
  • You are acquinted with modern software design principles – i.e. SOLID, Gang of Four, event-driven systems, etc.
  • You have experience with ASP.NET WebApi and ASP.NET MVC.
  • You have experience with relational databases, preferably SQL server.
  • You have experience with CI pipelines, in particular Azure DevOps.
  • You are familiar with distributed system design and messaging technology.
  • Experience with .NET 10 is a plus.
  • Experience with NServiceBus is a plus.
  • Experience with Azure cloud platform is a plus
  • – i.e. App Services, Application Insights, Azure Key Vault, Azure Functions, ServicesBus, etc.
  • Experience with Docker is a plus.
  • Experience with React is a plus
  • Experience with Kubernetes is a plus


Education & Soft-Skills:

  • You have a Bachelor's degree - Computer Science, MIS or equivalent
  • You are fluent in both spoken and written English.
  • French speaking is a plus
  • You can work independently but are also a team player.
  • You are conscientious and act professional.
  • You are motivated and have a positive mindset.
  • You do not shy away from asking difficult questions.
  • You are Customer centric
  • You are Solutions Minded
  • You have abilities to learn quickly
  • You are organized
  • You have verbal and written communication skills
  • You have real-world experience with Agile development methodologies such as Scrum


Ways of Working & Location:

  • Home working: 2 days/week - On site 3 days/week (mandatory). As a Keystone Solutions consultant, on-site days are performed at the client’s location.


Consultancy Advantages at Keystone Solutions:

  • Consultancy Nature of Work: Operate on-site within client teams as a Keystone Solutions consultant, building trust, delivering outcomes, and shaping best practices while representing our consultancy’s standards.
  • Dynamic Projects: Tackle diverse engineering challenges across client environments, from greenfield initiatives to complex application transformations, broadening your expertise beyond a single product or domain.
  • Turbo-Charged Learning and Development: Benefit from tailored learning paths, peer-to-peer coaching, certifications, and access to communities of practice that accelerate your growth in .NET, cloud, DevOps, testing, and architecture.
  • Ambition Skyrocketing within a Consultancy Framework: Progress through merit-based opportunities, rotating across engagements that match your ambitions—whether you aim to deepen technical mastery, lead squads, or influence architecture and delivery processes.


Keystone Solutions Values in Every Engagement:

At Keystone Solutions, our consultants—proudly called K-Stones—bring excellence, ownership, collaboration, and customer-centricity to every client project. As a K-Stone, you embody these values daily: building reliable software, communicating transparently, seeking continuous improvement, and delivering measurable value while respecting the client’s context and constraints.


Role-Specific Impact in a Consultancy Context:

As a .NET Developer with C#, you will apply modern engineering practices—covering design, development, testing automation, distributed systems, and DevOps—to deliver maintainable, observable, and scalable services for the client today, and you will be positioned to replicate and adapt these strengths across future Keystone Solutions engagements.


How to Apply:

If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal.