Senior .NET Developer (Blazor, UI focus) (K10249)

Titans Consulting

Brussel Hoofdstad

On-site

EUR 85,000 - 110,000

Full time

2 days ago

Be an early applicant

Get a reply from this recruiter

Your resume and cover letter, tailored to exactly what they’re hiring for.

Get past ATS filters

Job summary

NIHDI is seeking a Senior .NET Developer with a Blazor UI focus to design and deliver modern, secure and accessible business applications from the Blazor interface to the .NET services behind it. You will lead UI architecture, guide colleagues, and contribute to technical decisions within a 250-person ICT department.

The role covers hands-on development, API integration, authentication, security, testing and DevOps, with cloud-native Azure and shared design systems as a foundation.

Qualifications

Senior level with hands-on experience in Blazor UI and .NET backend.
Strong skills in C#, ASP.NET Core and REST API integration.
Proven ability to design accessible, secure and scalable user interfaces.
Experience with Azure cloud, DevOps pipelines and CI/CD practices.

Responsibilities

Lead UI architecture for Blazor-based applications and reusable components.
Implement secure authentication (OAuth 2.0 / OpenID Connect) and authorization.
Develop end-to-end features from UI to .NET services and APIs.
Collaborate with analysts, UX, security, and Platform Engineering teams.
Coach peers, conduct code reviews and promote engineering best practices.
Ensure testability with unit, component and UI automation tests.

Skills

C# and .NET

Blazor

UI development

ASP.NET Core

Azure

REST APIs

Security

Accessibility

DevOps / CI/CD

Testing (unit, UI)

Tools

MudBlazor

Azure DevOps

Git

Job description

Build the future of public health technology at NIHDI as a Senior .NET Developer with a user-interface focus. Your work will directly support digital services that contribute to the health and wellbeing of millions of people in Belgium. You will design and deliver secure, accessible, responsive and high-impact business applications end to end, from the Blazor user interface to the .NET services behind it, while guiding colleagues and contributing to sound technical decisions.

You will join an ICT department of approximately 250 professionals, actively engaged in more than 50 projects across different phases of development. NIHDI is transforming its application landscape toward a modern, cloud-native architecture on Microsoft Azure, using Azure Service Bus and containerised workloads to improve the way systems are built, integrated and scaled. A Platform Engineering team provides the shared libraries, the design system, the DevOps pipelines and the standards that every application team builds on.

NIHDI standardised its web user interfaces on Blazor so that one .NET skill set covers the whole application. The user interface is therefore not a separate discipline: it is the part of the .NET application that faces citizens, healthcare professionals and NIHDI employees, and it has to be accessible, consistent and fast. This transformation also includes the responsible integration of AI into business applications and into the way we develop them.

Join NIHDI to build smart, secure and purpose-driven digital services, and help shape the future of public health technology.

Job purpose

The Senior .NET Developer (Blazor, UI focus) is responsible for the design, development, integration and maintenance of modern business applications within NIHDI's application landscape, with particular ownership of their user interfaces. The role combines advanced hands-on development with technical leadership, coaching and close collaboration with analysts, architects, UX stakeholders, security specialists, the Platform Engineering team and operational teams.

As a senior member of the development team, the developer helps resolve complex technical challenges, makes well-founded design choices, improves engineering practices and supports other developers through coaching and code reviews. The role remains strongly hands-on and contributes directly to feature development, testing, troubleshooting and continuous improvement, on the user interface as well as on the services it depends on.

Key responsibilities

Technical leadership for the user interface: Provide technical direction for Blazor development across teams and promote a consistent approach to UI architecture, reusable components, coding standards and engineering practices, in line with the Platform Engineering team's standards.
Hands-on development: Dedicate a significant part of the role to developing features, reusable components, prototypes, technical improvements and bug fixes using C#, modern .NET, Blazor and Razor components, and the .NET Web APIs they rely on.
UI architecture and component design: Design scalable, maintainable and reusable front-end structures that align with NIHDI architectural principles, and contribute to the shared component library built on MudBlazor and the NIHDI design system.
Requirements analysis: Collaborate with functional and business analysts and UX stakeholders to clarify requirements, assess feasibility and translate user and business needs into robust technical solutions.
API integration: Integrate Blazor applications with REST APIs and JSON-based services, including typed clients, appropriate error handling, state management, validation and resilience; extend the Web APIs when a feature requires it.
Authentication and application security: Implement secure authentication and authorisation flows using OAuth 2.0 and OpenID Connect for the three audiences NIHDI serves (internal users, healthcare professionals and citizens, each with its own identity provider), and apply secure development practices throughout the application lifecycle.
Code quality and reviews: Ensure high code quality through structured pull-request reviews, refactoring, static analysis with SonarQube, coding standards and the development of clear, reusable and testable components.
Testing and quality assurance: Define and maintain unit tests, Blazor component tests (bUnit), service-level integration tests and, where appropriate, automated UI tests (Playwright) to support reliable releases and prevent regressions, following the test pyramid.
DevOps and delivery: Use Git, Azure DevOps repositories, boards and CI/CD pipelines to support controlled versioning, automated builds, testing and deployment to the Azure environments.
Coaching and knowledge sharing: Coach developers, share Blazor and accessibility expertise, document solutions and contribute to a culture of technical excellence and continuous learning.
Technology evaluation: Assess relevant .NET and web technologies and patterns, including AI-assisted development practices, and recommend adoption when they add sustainable value and align with NIHDI architectural and security decisions.

Key technical expertise

The Senior .NET Developer (Blazor, UI focus) should demonstrate recent, substantial hands-on experience in the following areas:

C# and modern .NET: Advanced proficiency in C# and current .NET (.NET 10 or later) development practices, including asynchronous programming, dependency injection, clean code and maintainable application design.
Blazor and Razor components: Recent hands-on experience developing production-grade Blazor applications, including the Blazor Web App model and its render modes (static server-side rendering, interactive Server, WebAssembly and Auto), prerendering and streaming rendering, component lifecycle, state handling, forms, validation and reusable component libraries such as MudBlazor.
HTML, CSS and responsive design: Strong command of semantic HTML, modern CSS and responsive design for consistent use across devices and screen sizes.
Accessibility: Practical experience delivering interfaces that meet WCAG 2.1 level AA: keyboard navigation, screen-reader support, contrast, focus management and accessible forms, including testing with assistive technologies.
REST API integration and JSON exchanges: Proven experience consuming and building REST APIs with ASP.NET Core, handling JSON exchanges and implementing robust validation, error handling and integration patterns.
OAuth 2.0 and OpenID Connect: Practical experience implementing secure authentication and authorisation in web applications using OAuth 2.0, OpenID Connect, JWT and claims-based authorisation.
Data access: Working proficiency with Entity Framework Core and SQL, sufficient to implement a feature end to end and to diagnose data-related issues.
Testing: Strong experience with unit testing, Blazor component testing (bUnit), service-level integration testing and, ideally, automated UI testing (Playwright). Able to design testable code and integrate automated tests into delivery pipelines.
Git, Azure DevOps and CI/CD pipelines: Advanced use of Git, branching and pull-request workflows, Azure DevOps repositories and boards, and CI/CD pipelines for automated build, test and deployment.
Engineering quality and security: Demonstrated focus on code quality, code reviews, application security, maintainability, observability and the development of reusable components.
AI-assisted development: Experience using AI coding assistants (GitHub Copilot, Claude Code or similar) in a professional setting, with sound judgement about when to rely on them and how to review their output.
Front-end architecture and design patterns: Ability to select and apply appropriate patterns for component design, separation of concerns, state management, dependency management and scalable application structure.
Cloud and containerised environments: Working knowledge of Microsoft Azure and an understanding of containerised deployment relevant to application delivery and troubleshooting.
Distributed systems awareness: Sufficient understanding of messaging (Azure Service Bus, NServiceBus) and distributed systems to collaborate effectively with integration-focused colleagues and diagnose end-to-end issues.
NIHDI ecosystem assets: Knowledge of SharePoint as a document management system or of legal document stores with WORM requirements is an asset where relevant to the assigned application domain.
Technical leadership and mentorship: Able to guide developers, provide constructive feedback, share knowledge and foster professional growth without losing the hands-on character of the role.
Collaboration: Works effectively with analysts, architects, UX stakeholders, security specialists, testers, the Platform Engineering team, operations teams and business representatives in a multidisciplinary public-service environment.
Problem-solving and decision-making: Strong analytical skills, able to identify root causes, compare options, explain trade-offs and make pragmatic, sustainable technical decisions.
User focus: Able to understand the needs of citizens, healthcare professionals and internal users, including users of assistive technologies, and translate them into clear, accessible and efficient digital experiences.
Communication: Communicates complex technical matters clearly to both technical and non-technical stakeholders and produces concise, useful technical documentation.
Resilience and adaptability: Able to manage changing technologies, priorities and requirements while maintaining quality, security and delivery commitments.
Continuous improvement: Actively follows relevant developments in .NET, Blazor, web standards, accessibility, security and software engineering, and applies them with sound judgement.

Mastery of French or Dutch and professional proficiency in English are required. Passive understanding of the second national language is considered an asset.

Expected seniority

The role requires a developer who can work autonomously on complex application challenges, take ownership from requirements through production support, influence technical choices, and raise the quality and consistency of the wider development team, in particular on the user-interface side. Seniority must be demonstrated through recent hands-on delivery, not only through coordination or advisory experience.

Required technical skills