Hybrid Senior Backend Developer – C# .NET

at Puzzel

• Job title: Senior Backend Developer – C# .NET
• Job type: Full Time
• Experience level: Senior
• Salary: Not specified
• Degree requirement: Bachelor's Degree
• Tech skills: Distributed Systems, Java, Postgres, SQL, TypeScript, Go
• Location requirements: Hybrid, Aarhus, Denmark

About the role

• Senior Backend Developer responsible for maintaining core backend services at Puzzel, a cloud-based contact center solutions provider. Ensuring high availability, security, and optimizing backend system performance.

Responsibilities

• Design, build, and maintain scalable backend services powering our Core Platform Services.
• Write clean, maintainable, and well-documented code that supports high availability and rapid iteration.
• Own the performance and optimization of critical services, identifying bottlenecks, reducing latency, and ensuring systems can scale to meet growing demand.
• Collaborate closely with product, design, and other engineering teams to deliver performant and reliable features.
• Design and maintain secure, well-documented APIs that enable seamless integration between core services and client applications across the CX ecosystem.
• Participate in system architecture discussions, contributing to design decisions and technical direction.
• Continuously explore and apply new technologies to improve performance, scalability, and developer experience.
• Monitor system health and respond to incidents, implementing robust observability practices and participating in on-call rotations to ensure platform reliability.
• Mentor and guide other developers through code reviews, pair programming, and knowledge sharing, helping to elevate the technical capabilities of the broader team.

Requirements

• 5 years of backend development experience working on a SaaS product, in a backend or fullstack capacity.
• Proven experience building and maintaining large-scale distributed systems or data-heavy applications.
• Strong proficiency in C# (our primary language) or another modern backend language such as TypeScript, Java, or Go, with willingness to work primarily in C#.
• Solid understanding of system design, API development, and microservice architecture.
• Effective communication skills in English and a collaborative mindset.
• Experience with relational databases (SQL Server, PostgreSQL, or similar) and a solid understanding of database design, optimization, and query performance.
• Strong focus on testing and quality, with experience writing unit, integration, and end-to-end tests to ensure system reliability.
• Understanding of security best practices, particularly around authentication, authorization, data protection, and secure API design.
• Experience working in agile environments with modern development practices including CI/CD pipelines, version control (Git), and collaborative code review processes.

Benefits

• Competitive fixed salary
• Flexible, hybrid approach to working; split your time between the office and home
• You get to be part of a fun, driven and supportive team
• Generous pension contribution
• Annual Summer and Christmas parties
• Excellent development opportunities and a great company culture