.NET Developer

Mission Overview:Keystone Solutions is seeking a Confirmed Back-End Developer to join us as a consultant on a mission at our client’s site. As a Keystone Solutions consultant, you will reinforce the client’s teams and contribute to the evolution of their core business applications, delivering high-quality back-end solutions while collaborating closely with the client’s stakeholders.Consultancy Model at Keystone Solutions:Consultancy nature of work: You will operate on-site at client locations as a Keystone Solutions consultant, embedded with the client’s team while supported by Keystone’s community of experts.Dynamic projects: Tackle diverse technical challenges across various client environments, giving you exposure to multiple industries and architectures.Turbo-charged learning and development: Access continuous learning, mentoring, and peer support from Keystone Solutions to broaden your skills and accelerate your growth.Ambition skyrocketing within a consultancy framework: Build a high-impact career through varied client engagements, with clear pathways for advancement as a valued “K-Stone.”Key Responsibilities:Contribute to the evolution of the client’s core business applications as a back-end developer, reinforcing the client’s teams as a Keystone Solutions consultant.Understand and work with UML models.Know, use, and manage Microsoft SQL Server from versions 2016 to SQL Server 2025.Know, use, and manage an Oracle database, version 19.Apply design patterns based on the recommendations of the architect.Develop REST services using .NET Framework and .NET 8+.Develop interfaces in ASP.NET WebForms / MVC on .NET 4.5 and above.Develop and integrate using XML and JSON.Know and use W3C standards.Know and use WebAPI, WCF REST, WCF, and Web Services.Know and use Azure DevOps with Git and TFVC.Use Entity Framework Core.Leverage practical knowledge of Redgate tools (considered a plus).Carry out all responsibilities under Keystone Solutions’ consultancy model, working closely with the client’s teams and processes.Required Skills and Experience:Role: Confirmed Back-End Developer (mandatory); most recent experience: this year..NET — Expert level; most recent experience: this year..NET Core — Expert level; most recent experience: this year.Agile — Confirmed; most recent experience: any time.ASP.NET — Confirmed; most recent experience: 1 to 3 years ago.ASP.NET MVC — Confirmed; most recent experience: 1 to 3 years ago.Azure DevOps — Confirmed; most recent experience: this year.Git — Confirmed; most recent experience: 1 to 3 years ago.JSON — Confirmed; most recent experience: this year.RESTful API — Confirmed; most recent experience: 1 to 3 years ago.Scrum — Confirmed; most recent experience: this year.SOAP API — Nice to have; most recent experience: any time.Visual Studio — Expert; most recent experience: 1 to 3 years ago.XML — Confirmed; most recent experience: any time.Understanding of UML models.Proficiency with Microsoft SQL Server 2016 through SQL Server 2025.Proficiency with Oracle Database, version 19.Ability to apply design patterns as recommended by an architect.Experience developing REST services in .NET Framework and .NET 8+.Experience with ASP.NET WebForms / MVC on .NET 4.5 and above.Fluency with XML and JSON.Knowledge and use of W3C standards.Knowledge and use of WebAPI, WCF REST, WCF, and Web Services.Experience with Azure DevOps, including Git and TFVC.Practical knowledge of Redgate tools (a plus).Experience with Entity Framework Core.Languages:The service you will integrate is predominantly French-speaking; therefore, an excellent command of French is indispensable.French — Native level.English — Passive knowledge.Dutch — Passive knowledge.Work Location:On-site at the client’s main address: Avenue de l'Astronomie, 14 - 1000 Bruxelles.Keystone Solutions Values in a Consultancy Context:As a K-Stone, you bring craftsmanship, ownership, curiosity, collaboration, and integrity to every client engagement.We prioritize client impact, transparent communication, and high engineering standards in all consulting missions.You will represent Keystone Solutions on-site, embodying our values while delivering measurable outcomes for the client.Role-Specific Consultancy Advantages:Apply your .NET back-end expertise across multiple client scenarios, from legacy modernization to cloud-first services and API ecosystems.Gain breadth and depth by working with varied databases (SQL Server 2016–2025, Oracle 19), integration stacks (WebAPI, WCF, SOAP), and delivery pipelines (Azure DevOps with Git and TFVC).Shape solutions in close collaboration with architects, translating design patterns into robust, scalable services in .NET Framework and .NET 8+.If you are ready to tackle technical and strategic challenges in a dynamic consultancy environment, apply today at Keystone Solutions Career Portal.