.Net Developer

Keystone Solutions is seeking a Senior .NET Developer for a consultancy mission within the client's Transport Execution Management domain. As a Keystone Solutions consultant, you will take ownership of designing and building high-quality, well-tested software solutions. You will work closely with the client's solution designer and business stakeholders to translate ideas into effective, reliable applications, while developing a deep understanding of the business context.

Beyond strong technical expertise, we are looking for someone who shows initiative, communicates clearly, contributes actively to the team, and is willing to go the extra mile when needed. You are respectful and calm in your interactions. Independence is key in this role: taking full responsibility for delivering complete solutions is part of your daily work. At the same time, you value teamwork and knowledge sharing. In line with the client's values, you bring professionalism and a constructive attitude that helps the team move forward.

• →Design and build high-quality, well-tested software solutions within the Transport Execution Management domain.
• →Collaborate closely with the client's solution designer and business stakeholders to translate ideas into robust, reliable applications.
• →Apply Clean Code, Clean Architecture, and SOLID principles to deliver maintainable systems.
• →Develop secure, performant .NET Core Web APIs and ensure strong API design practices.
• →Leverage Azure services and PaaS components, applying event-driven patterns where appropriate.
• →Create meaningful, maintainable automated unit tests to ensure software quality.
• →Contribute to CI/CD and DevOps practices using Azure DevOps, including containerized deployments with Kubernetes and Docker.
• →Integrate reliably with backend APIs and design Android applications that can handle offline usage, local persistence, synchronization, conflict handling, and recovery when connectivity is restored.
• →Model, query, and optimize relational databases using strong SQL and database design skills.
• →Collaborate effectively using Git, applying appropriate branching strategies.
• →Explain technical choices clearly to both technical and non-technical stakeholders.
• →Work on-site at the client location in Brussels a minimum of 2 days per week, operating with professionalism, independence, and a constructive, team-oriented mindset.

• .NET development: more than 5 years of experience.
• Azure Cloud development: more than 3 years of experience.
• .NET Core Web API development: over 3 years of experience.
• Experienced in unit testing code.
• Demonstrable experience with Clean Code, Clean Architecture and SOLID principles.
• Minimum 2 days onsite in Brussels.
• You communicate fluently in Dutch or French (spoken and written) at least C2 level.
• You communicate fluently in English (spoken and written) with at least level C1.

• .NET development – demonstrates strong mastery of the .NET ecosystem, including language features, LINQ, async/await, security practices, data structures and design patterns.
• Code quality & craftsmanship – writes clean, maintainable and SOLID code that follows proven engineering practices.
• Web API design & development – designs secure, performant .NET Core Web APIs.
• Azure cloud – leverages Azure services, PaaS components, and event-driven patterns effectively.
• Unit testing & test quality – creates meaningful, maintainable and automated unit tests.
• CI/CD & DevOps practices – sets up robust Azure DevOps pipelines and manages containerized deployments with Kubernetes & Docker.
• API integration & offline/online synchronization – integrates reliably with backend APIs and designs Android applications that can handle offline usage, local persistence, synchronization, conflict handling and recovery when connectivity is restored.
• SQL & database design – models, queries, and optimizes relational databases.
• Git & version control – applies branching strategies and collaborates efficiently using Git.
• Communication – explains technical choices clearly.

• Consultancy Nature of Work: You will be employed by Keystone Solutions and work on-site with our client as a trusted consultant, embedded in their teams to deliver impactful outcomes.
• Dynamic Projects: Access diverse challenges across multiple client engagements over time, broadening your technical toolkit in .NET, Azure, APIs, CI/CD, containers, and mobile/offline synchronization patterns.
• Turbo-Charged Learning and Development: Benefit from tailored learning paths, certifications, mentoring, and knowledge-sharing sessions to accelerate your growth across the Microsoft and cloud ecosystem.
• Ambition Skyrocketing within a Consultancy Framework: Build a fast-paced, upward trajectory through varied missions, taking on increasing responsibility and ownership while shaping solutions that matter.

• Being a K‑Stone means bringing excellence, integrity, curiosity, and collaborative impact to each project.
• We prioritize customer value, craftsmanship, and clear communication, ensuring trust and long-term partnerships with our clients.
• We champion knowledge sharing and team play, so you grow while helping the client's teams advance.

• Apply senior-level .NET engineering practices to mission-critical Transport Execution Management scenarios.
• Deepen expertise in Azure PaaS, event-driven design, and secure API development across different client contexts.
• Lead by example in code quality, testing, DevOps automation, and container-based delivery.
• Expand your scope into API integrations and mobile/offline synchronization challenges where Android applications interact with backend services.

• Location: Brussels (minimum 2 days on-site at the client).
• Languages: Dutch or French at C2 level and English at C1 level, spoken and written.
• Contract: Consultancy mission through Keystone Solutions, working closely with the client's teams.

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