Senior Enterprise C/C++ and .NET Developer

Are you an experienced Back-end Developer or Fullstack developer (Blazor) who thrives on security, scale, and high-impact engineering?Do you want to modernize mission-critical enterprise software, evolve a global-ready product, and help shape the future of secure certificate lifecycle management?Then this is your chance to join a technically elite core team and make a direct impact on a platform used across complex IT, OT, and IoT landscapes worldwide.About the organization Our client is a fast-growing Dutch scale-up with global ambitions, developing cutting-edge enterprise solutions for PKI Certificate Lifecycle Management (CLM). Their software automates certificate discovery, provisioning, and renewal across large hybrid environments - from data centers to cloud-native infrastructures. The environment is dynamic, flexible and ambitious: the platform is evolving rapidly, and your expertise will directly influence its architecture, scalability, and security posture.About the role As a Senior Back-end Developer, you'll work hands-on on both legacy modernization and greenfield development. You'll upgrade and extend a foundational C/C++ codebase, while designing and building new components in C# / ASP.NET within a modern enterprise ecosystem. Security, reliability, and maintainability are critical. You'll act as a technical sparring partner, contribute to architectural decisions, and help evolve the platform into a global-scale product. If you enjoy deep engineering challenges and meaningful technical ownership, this role will fit you perfectly.What you'll doModernize and extend a legacy C/C++ enterprise codebaseDesign and build new back-end components in C# / ASP.NETStrengthen the platform's security, scalability, and reliabilityIntegrate with cloud-native and enterprise services (e.g., Entra ID / MS Graph)Work with containerization and orchestration (Docker, Kubernetes)Contribute to CI/CD automation and infrastructure tooling (Ansible)Implement robust, secure coding practices and perform code reviewsBring new product features to life in a fast-moving environmentCollaborate closely with developers and architects in a lean, high-performing teamWho you areA pragmatic, seasoned engineer with strong ownershipComfortable working in small, high-impact teamsCapable of bringing modern architecture into complex legacy systems for enterprise companiesSomeone who naturally thinks in terms of security, robustness, and long-term maintainabilityNot afraid to dive deep into systems and improve them from withinWhat you bringEU passport (needed for security compliance)Based in the NetherlandsStrong expertise in secure coding, code review, and automationSolid experience with C# and ASP.NETStrong C/C++ skills for maintaining and evolving legacy componentsExperience in Enterprise Software environments, not in embedded environments!!!!!Proficient in SQL, RESTful APIs, multithreadingHands-on experience with Docker, Kubernetes, and AnsibleInterest in cloud identity integrations such as Entra ID / MS GraphNice to havegRPC / Protobuf.NET 8+ / C# 12+Experience with BlazorGenerative AI-assisted developmentOpenSSL knowledgeApplied interest in post-quantum cryptographyMySQL administration experienceWhat's in it for youWork on a platform with high security, global scale, and real-world impactA role with significant technical influence and architectural inputHybrid working: one day per week in Utrecht, the rest remoteA highly skilled, collaborative engineering team with deep domain expertiseFreedom, responsibility, and room to experiment with modern technologiesA transparent, flat organization where your contribution directly shapes the product and the company's growth trajectoryWhy this role matters In this position, you'll help transform a mission-critical enterprise platform used across diverse and security-sensitive environments. You won't just write code - you'll shape the foundations for trusted digital communication at global scale. Your expertise will directly advance security, reliability, and innovation in a domain where precision truly matters. Are you the senior back-end engineer who combines modern engineering mindset with a passion for secure, scalable enterprise software?Then we'd love to hear from you!