IMS Core Engineer - Systems & Debugging (m/f/d)

About us:
Committed to building the next generation of 100% software-based mobile networks, ng-voice is creating innovative mobile infrastructure solutions and making them accessible for operators and enterprises that want to deploy future-proof networks.

To further strengthen the robustness and scalability of our IMS platform, we are building a dedicated Level 3 engineering team focused on advanced debugging, root cause analysis, and production excellence.

As a Senior IMS Core Engineer – Systems & Debugging (m/f/d) at ng-voice, you will work at the heart of our IMS core systems, ensuring stability and correctness of complex telecom software in production environments. This is a highly hands-on engineering role focused on deep technical analysis, complex debugging, and resolution of customer-impacting issues. You will collaborate closely with L2 support, QA, and development teams to ensure our systems remain reliable and production-ready.

Tasks:
What you will do as IMS Core Engineer - Systems & Debugging (m/f/d):
• Investigate and resolve complex production issues within IMS core components.
• Perform advanced C-level debugging, including analysis of deadlocks, race conditions, memory corruption, and concurrency issues.
• Conduct structured root cause analysis across distributed telecom systems.
• Analyse SIP and Diameter signalling flows and end-to-end IMS call scenarios.
• Navigate and interpret complex 3GPP specifications to validate expected behaviour and implementation. 
• Implement high-quality bug fixes and stability improvements in the codebase.
• Collaborate closely with L2 support, QA, and R&D to reproduce, analyse, and resolve issues.
• Continuously improve diagnostics, logging, and observability of IMS components.

Requirements:
What we are looking for in an IMS Core - Systems & Debugging (m/f/d):

Our ideal new colleague brings a strong software engineering background combined with deep IMS knowledge and advanced debugging capabilities.

This role is open to experienced medior and senior engineers with at least 6+ years of professional experience in complex telecom or distributed software systems.

We are looking for engineers who are highly analytical, comfortable working in large codebases, and motivated by solving difficult production issues.
 
Required skills & experience
• At least 6+ years of professional software engineering experience.
• Strong hands-on experience in C programming, with proven expertise in advanced debugging of complex systems.
• Demonstrated experience performing structured root cause analysis in distributed environments.
• Deep understanding of IMS architecture and call flows.
• Strong knowledge of SIP, Diameter, and related telecom protocols.
• Experience working with large, complex, production-grade codebases.
• Ability to navigate and interpret 3GPP specifications.
• Strong analytical, structured problem-solving and communication skills.
• Initiative and ownership mindset; ability to drive multiple issues forward independently in a fast-changing priority environment.

Strongly preferred
• Hands-on experience with Kamailio internals.
• Experience debugging SIP proxy or IMS core implementations.

Benefits:
A little more about our culture and why you should join • Work-Life-Balance is a priority: Flexible working that suits you - we live and breathe a hybrid remote culture and don't mind where and when you work    
• We are committed to building a diverse team that represents a variety of backgrounds, perspectives, and skills in a traditionally not very diverse industry   
• We offer you the culture of a fast-growing start-up with the maturity of an enterprise company
• We are more interested in your experience and knowledge than formal degrees 
• Entrepreneurial culture and flat hierarchies   
• Mobility benefit, fitness benefit, language class benefit and wellness benefit (for full-time employees)
• Home office budget (for full-time employees)