atNorth is a leading Nordic data center company providing sustainable, high-performance computing and colocation solutions across Iceland, Sweden, Finland and Denmark.

We design mission-critical ecosystems powered by 100% renewable energy and circular economy principles, staying ahead through a relentless focus on reliability, security, and performance.

We believe world-class technology requires a world-class culture. Our people-first mentality ensures that technical excellence and human wellbeing go hand in hand. Built on collaboration, ownership, and trust, our environment empowers individuals to take responsibility, grow their expertise, and make a real impact.

By joining our international team, you play a direct role in shaping the future of sustainable digital infrastructure while supporting the communities and industries we serve.

Senior Back-End Developer at atNorth

We’re looking for an experienced Senior Back‑End Developer with strong .NET skills to help us build secure, scalable, and high‑performance backend services. In this role, you will design and develop RESTful APIs, build reliable integrations, and contribute to the backend architecture powering our products.

You’ll work closely with product owners, architects, frontend developers, and DevOps to deliver clean, well‑tested, and well‑documented services. You’ll also support integrations with internal and external systems, including messaging via Azure Service Bus and data workflows with Microsoft Fabric.

This is a great opportunity for someone who enjoys solving complex engineering challenges and shaping modern backend platforms.

This role will be based in atNorth's ICE01 Datacenter in Reykjavik, Hafnarfjörður.

Key responsibilities:

API & backend engineering

• Design, develop, and maintain secure, high‑performance RESTful APIs using .NET

• Ensure scalability, reliability, and maintainability through clean code and strong architecture

• Build and maintain integrations with internal systems and third‑party services

• Participate in code reviews, technical discussions, and continuous improvement

Quality, testing & CI/CD

• Apply TDD principles and write high‑quality unit and integration tests

• Use tools such as xUnit or NUnit to ensure reliable test coverage

• Work with DevOps to integrate testing into CI/CD pipelines

• Perform performance, load, and stress testing to validate system behavior

Documentation & developer experience

• Produce clear, accurate API documentation using OpenAPI/Swagger

• Maintain Postman collections and other developer‑friendly tools

• Ensure documentation is version‑controlled and kept up to date

• Provide examples, guidelines, and error‑handling documentation

Integrations, data & operations

• Build integrations using Azure Service Bus and event‑driven workflows

• Work with Microsoft Fabric for reporting, analytics, and data retrieval

• Collaborate with data and analytics teams to meet downstream requirements

• Monitor production systems, troubleshoot issues, and support incident resolution

Your profile:

Backend & API development

• Solid experience developing backend services and RESTful APIs with .NET

• Strong understanding of API design principles (authentication, versioning, error handling, etc.)

• Experience using OpenAPI/Swagger and Postman

Testing & quality engineering

• Hands‑on experience with TDD and writing unit/integration tests

• Experience integrating automated tests into CI/CD pipelines

• Familiarity with performance and load testing

Cloud, security & architecture

• Understanding of secure coding practices and common API security standards

• Experience with event‑driven or message‑based architectures (e.g., Azure Service Bus)

Engineering practices & collaboration

• Proficiency with Git and modern branching/PR workflows

• Strong debugging and problem‑solving skills

• Comfortable working in cross‑functional engineering teams

Nice to have:

Data & analytics

• Experience with Microsoft Fabric for analytics or reporting

• Background working with data platforms or data‑centric APIs

Architecture & system design

• Knowledge of CQRS, event sourcing, and/or microservices patterns

• Experience designing asynchronous or event‑driven systems

Observability & reliability

• Familiarity with logging, metrics, and monitoring tools

• Experience working in security‑sensitive or regulated environments

Leadership & engineering excellence

• Exposure to Domain‑Driven Design concepts

• Ability to mentor other engineers or support engineering standards

About the atNorth Culture

We believe that sustainable success starts with the wellbeing of our people. For us, an open, transparent, and inclusive culture is more than a priority, it is the core of how we lead and innovate.

We don’t just talk about culture; we nurture it. Through regular one-to-one engagements and monthly wellbeing surveys, we listen carefully to our teams, ensuring that every voice is heard and every opportunity for improvement is embraced.

We recognize that innovation and collaboration thrive where people feel truly connected, which is why we come together each week to share ideas, strengthen relationships, and nurture a sense of belonging, sometimes over a simple breakfast and good conversation.

At atNorth, we are building a community where you can do your best work and shape a sustainable future together.