Senior Backend Developer – C# .NET

Senior Backend Developer – C# .NET
Aarhus, Denmark OR Arendal, Norway

Puzzel: The Low-Down

Puzzel is a leading provider of cloud-based contact centre solutions, empowering businesses to deliver exceptional customer service. Our platform combines omnichannel contact centre, workforce management, and AI-driven analytics to optimize customer interactions and operational efficiency.

With 25 years' experience since our foundation in Norway, we're already #1 in the Nordics, growing rapidly in the UK and expanding into the Netherlands and Finland in 2024, but our ambition is to become the clear European market-leader in the coming years

Why we're proud

• 2024 CX Awards Winner, 'Best Mid-Market Contact Center Platform'
• Puzzel was recognised as the 'most innovative European-founded CCaaS provider' and top 3 globally by Frost & Sullivan in 2023
• Best Practices Company of the Year 2023
• Consistently high Glassdoor rating
• 2023 customer NPS score of 37
• Puzzel places high importance on work-life balance and flexible working hours - as recognised by Flexa, placing th overall for work:life balance in 2025
• We are working with Mercer on salary benchmarking, to ensure pay equality and market competitiveness

Key Data Points

• €57m revenue in FY 2024 (up from €50m in 2023)
• Currently ~300 employees
• Used by more than 1100 businesses across 40 countries
• Servicing ~60,000 customer service agents on a daily basis + 800 million customer interactions yearly

What you'll do

The Senior Backend Developer will be an integral part of our Core Platform team, who build and maintain the functionality of our core CX ecosystem: think ID/login, SMS Gateway, Voice Calls, Knowledgebase, Master Data – all of the core functionality that enables customers to get in touch with the customer service department and in turn, for the customer service agents to have access to information about the customer.

As part of the team, you'll work on building and evolving these systems — ensuring that these critical systems are reliable, secure, and highly available – enabling seamless customer interactions and empowering agents with the real-time information they need to deliver exceptional service.

It's important to mention that this is an individual contributor role with no direct reports, so we're looking for hands on developers at a senior level.

Key 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.
• Own the performance and optimization of critical services, identifying bottlenecks, reducing latency, and ensuring systems can scale to meet growing demand
• 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.

The Must Haves

• 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.

The Nice to Haves

• Experience with technologies such as .NET Core, SQL Server RabbitMQ, or Redis.
• Familiarity with containerisation and orchestration (Docker, Kubernetes).
• Experience with CI/CD tools like Azure DevOps or similar.
• Knowledge of cloud-native architectures and distributed processing.
• Knowledge of modern tools for development like Cursor, Co-pilot and similar.
• Experience/knowledge of Product Operating Model

The location

Aarhus or Arendal.

The team typically go in 2-3 days/week, with the rest working from home; the office is there 5 days/week if so desired

What's In it for You? 

• 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

What to expect from the interview process

• Screening call with Talent Acquisition
• 1st interview with the Development Manager + Product Manager
• 2nd interview with Lead Developer(s) + Development Manager
• Psychometric assessments
• Final interview with Dev Manager + VP of Engineering

Puzzel Values

• Built on Trust – trust is an intrinsic Nordic value, upon which Puzzel has been built. We trust each other and our customers and partners trust us.
• Stronger Together – working together in a genuinely collaborative way, with a shared purpose, we have an empowered organisation that is better equipped to delight customers and partners.
• Stay Hungry – have a continuous hunger to raise our game, innovate and be the best we can be professionally.

Diversity & Inclusion

We want everyone at Puzzel to be their true, authentic selves at work irrespective of nationality, race, ethnicity, religion, sexual orientation, gender identity, physical ability, age, or economic background.

Whilst we are proud to already have a diverse workforce from across the globe, we are aware that things could always be improved – for example, we currently have a ratio of female 26:74 male employees, which whilst not uncommon for the tech industry (average in SaaS is 26% female), it's far from ideal. So, what are we doing to improve this?

• Our Global Leadership Team (C-suite) has shifted from 100% male to 50 male: female in the past 18 months.
• We have increased our % of female hires from 23.6% in 2021 to 38.5% in 2023.
• We are partnering with the likes of Flexa, who have significantly higher-than-average talent pools of candidates from diverse backgrounds.
• We are working with State Employment initiatives in Norway and Sweden to bring candidates through internship/apprenticeship routes and are investigating similar initiatives in the UK and Bulgaria.
• By raising awareness and transparency, we are hoping to further attract a diverse workforce.

We are continuously striving to foster an inclusive and diverse environment, where everyone is celebrated for who they are. If there is anything we can do to support you in the interview process, or beyond, please let us know.

One Last Thing

Even if you feel you are only a 75% match for this role, we still want to hear from you. This list is purely indicative. Skills can always be learnt.

Please note that we are not able to provide sponsorship for this role, so you must have eligibility to work in the country you are applying for.

By applying you accept the terms of our Privacy Notice which can be found on our website. Puzzel are not considering candidates that do not have a work permit in the country we are hiring in.