Senior Enterprise C/C++ and .NET Developer

Spilberg; Utrecht; On-site; EUR 60,000 - 80,000; Full time

Benefits offered by this job

Hybrid working model

Collaborative engineering team

Opportunity for innovation

Job summary

A fast-growing technology firm in Utrecht seeks an experienced Senior Back-end Developer to modernize and enhance their enterprise platform. You will work on both legacy modernization and new component development using C# and ASP.NET. The role offers hybrid working conditions, a collaborative team, and opportunities to significantly influence product architecture and security. This is an ideal position for engineers passionate about secure, scalable software solutions.

Qualifications

• Strong expertise in secure coding, code review, and automation.
• Solid experience with C# and ASP.NET for enterprise applications.
• Experience in maintaining and evolving legacy components in C/C++.
• Proficient in SQL and RESTful APIs, with understanding of multithreading.

Responsibilities

• Modernize and extend a legacy C/C++ enterprise codebase.
• Design and build new back-end components in C# / ASP.NET.
• Strengthen the platform's security, scalability, and reliability.
• Integrate with cloud-native and enterprise services.
• Implement robust, secure coding practices and perform code reviews.

Skills

C#

ASP.NET

C/C++

SQL

RESTful APIs

Docker

Kubernetes

Ansible

Security compliance

Cloud identity integrations

Education

EU passport

Tools

Docker

Kubernetes

Ansible

Job description

Overview

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 do

• Modernize and extend a legacy C/C++ enterprise codebase
• Design and build new back-end components in C# / ASP.NET
• Strengthen the platform\'s security, scalability, and reliability
• Integrate 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 reviews
• Bring new product features to life in a fast-moving environment
• Collaborate closely with developers and architects in a lean, high-performing team

Who you are

• A pragmatic, seasoned engineer with strong ownership
• Comfortable working in small, high-impact teams
• Capable of bringing modern architecture into complex legacy systems for enterprise companies
• Someone who naturally thinks in terms of security, robustness, and long-term maintainability
• Not afraid to dive deep into systems and improve them from within

What you bring

• EU passport (needed for security compliance)
• Based in the Netherlands
• Strong expertise in secure coding, code review, and automation
• Solid experience with C# and ASP.NET
• Strong C/C++ skills for maintaining and evolving legacy components
• Experience in Enterprise Software environments, not in embedded environments
• Proficient in SQL, RESTful APIs, multithreading
• Hands-on experience with Docker, Kubernetes, and Ansible
• Interest in cloud identity integrations such as Entra ID / MS Graph

Nice to have

• Experience with Blazor
• OpenSSL knowledge
• Applied interest in post-quantum cryptography

What\'s in it for you

• Work on a platform with high security, global scale, and real-world impact
• A role with significant technical influence and architectural input
• Hybrid working: one day per week in Utrecht, the rest remote
• A highly skilled, collaborative engineering team with deep domain expertise
• Freedom, responsibility, and room to experiment with modern technologies
• A transparent, flat organization where your contribution directly shapes the product and the company\'s growth trajectory

Why 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!