.NET C# developer (REF2679)

Mission Overview:

As a Keystone Solutions consultant, you will join a consultancy mission to support our client in the mobility sector. The client is a key player in mobility offering more than 1000 parking lots across 9 European countries and is transforming to become a more digitally oriented player. You will contribute as a C#/.NET Developer within agile development teams, performing the responsibilities below under Keystone Solutions’ consultancy model while working closely with the client.

Consultancy Nature of Work:

This is a consultancy engagement delivered by Keystone Solutions. You will collaborate with the client’s teams, contribute on site at the client location, and operate within Keystone’s consultancy framework—bringing best practices, professionalism, and adaptability to each engagement.

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 the above responsibilities will be performed as a Keystone Solutions consultant, working closely with the client’s teams and stakeholders.

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) at the client site as part of the consultancy mission.

Dynamic Projects:

As a Keystone Solutions consultant, you will have the opportunity to contribute to client initiatives that span application development, testing automation, and distributed systems—enhancing your exposure to diverse technical challenges within the client’s environment.

Turbo-Charged Learning and Development:

Working through Keystone Solutions enables broad learning experiences across modern .NET practices and adjacent technologies present in the client context, supporting continuous professional growth through hands-on, real-world engagements.

Ambition Skyrocketing within a Consultancy Framework:

Keystone Solutions fosters career growth by enabling consultants to tackle impactful client problems, drive improvements, and refine their craft across a variety of project scopes, from greenfield development to application transformations.

Keystone Solutions Values in Action:

Being a K-Stone means bringing customer centricity, solution-minded thinking, professionalism, and collaboration to every client interaction—ensuring high-quality delivery and lasting impact on each engagement.

Application:

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

Mission Overview:

This opportunity is a consultancy mission delivered by Keystone Solutions. As a Keystone Solutions consultant, you will be embedded within the client’s agile development teams to design, build, and evolve modern C#/.NET applications. You will perform all responsibilities and meet all requirements listed below while working closely with the client under Keystone Solutions’ consultancy model.

About the Client and Assignment Context:

Our client is a key player in mobility offering more than 1000 parking lots across 9 European countries. In order to better serve its 100 million annual customers, our client is transforming itself to become a more digitally-oriented player. To support this undertaking, Keystone Solutions is strengthening the client’s agile development teams with strong C#/.NET developers.

Key Responsibilities (delivered as a Keystone Solutions consultant):

• 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.

Required 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) at the client location, as part of Keystone Solutions’ consultancy engagement.

Why Keystone Solutions Consultancy:

• Consultancy nature of work: Operate on-site with the client as a Keystone Solutions consultant, integrating with their product teams while benefiting from Keystone’s community, coaching, and delivery standards.
• Dynamic projects: Tackle diverse technical challenges across client initiatives, from greenfield builds to modernization, API-driven integrations, distributed systems, and performance optimization.
• Turbo-charged learning and development: Access curated learning paths, certifications, peer mentoring, and knowledge-sharing sessions focused on C#, .NET, testing automation, Azure, CI/CD, and scalable architectures.
• Ambition skyrocketing within a consultancy framework: Accelerate your career through varied client engagements, visible impact, and tailored growth plans that expand responsibilities from development to design leadership.

Keystone Solutions Values in a Consultancy Context:

• Customer centricity: Align solutions to real user and business needs at each client site.
• Craftsmanship: Write clean, tested, maintainable C#/.NET code and robust automation.
• Ownership: Proactively improve processes, reliability, and operational excellence.
• Collaboration: Communicate clearly across teams on APIs, deployments, and incidents.
• Integrity: Deliver on commitments and advocate for sustainable engineering practices.
• Curiosity and learning: Embrace continuous improvement through new tools and patterns.
• Being a K‑Stone means bringing these values to every client project, every day.