Senior Backend Software Engineer

Spirii is looking for a Senior Backend Software Engineer. If you are passionate about cloud software development, team collaboration, and creating outstanding backend code, join Spirii's fantastic growth journey to lead the way for a sustainable future. Spirii develops and provides world-class charging products and digital solutions to customers with electric cars. Our Digital Development department is proud to drive a listen, learn, and lead culture that allows us to constantly improve our ways of working, including how we adopt AI to raise the quality and speed of our engineering. As a Senior Backend Software Engineer in our Payments team, you will help enhance the backbone of the Spirii platform that turns charging data into accurate invoices, credit memos, and payouts. It's a domain where correctness and financial data integrity are non-negotiable. You will report to an Engineering Manager and work closely with CPH and near-shore colleagues, as well as Finance and partner teams. What You Will Do Together with your team, you will be responsible for: Designing, building, and maintaining scalable, secure backend services and cloud-native queue-based pipelines (Node.js, NestJS, TypeScript) that power data ingestion, processing, and invoice generation at high throughput. Ensuring data quality through correct aggregation and safe handling of late or updated records. Building and maintaining integrations with internal services and our ERP system. Significantly contributing to architectural decisions and solution design for cloud-native, distributed, event-driven systems on AWS. Driving automated testing and observability to protect billing correctness and catch data discrepancies early. Mentoring other engineers and raising the technical bar of the team through code review, pairing, and constructive feedback. Operating independently on ambiguous, cross-team problems with minimal oversight. Using AI coding assistants and agentic workflows to accelerate development and automate repetitive tasks while helping the team adopt AI safely in a financially sensitive codebase. Who You Are Like to explore innovative technologies, including AI tools and agentic workflows, and continuously expand your skills. Ambitious and execution-focused, with strong ability to balance functional and non-functional requirements when designing solutions. A proven track record of taking end-to-end ownership of complex backend systems and actively maintaining operational awareness. Skilled at breaking down complex, ambiguous initiatives into vertical slices that deliver value incrementally; you default to shipping in small, regular batches rather than big-bang releases. Comfortable working in Agile, cross-functional teams (backend, frontend, Finance, partners), and an active participant in creating an open, collaborative environment. Excellent English communication skills and the ability to interact with all levels of the organization, internally and externally with partners/customers. Qualifications Bachelor's degree in Computer Science, Software Engineering, or a related field (or equivalent experience). 7+ years of professional software development experience. Extensive hands-on experience designing and scaling production backend systems, including having designed event-driven, queue/job-based architectures. Strong experience building TypeScript or JavaScript (Node.js, NestJS) microservices on cloud platforms such as AWS. Experience leading design discussions, mentoring engineers, or acting as a technical point of contact for a team or domain. Hands-on experience with test-driven development, test automation, integration and load testing. Strong SQL and data-modelling skills, with the discipline needed for financially accurate, auditable data. Experience integrating external and internal IT systems, and solid API design. Experience with developing secure software is a plus. Knowledge of Redis and NoSQL databases is an advantage. Experience working with or integrating ERP systems (e.g. Microsoft Business Central) is an advantage. Experience with billing, payments, invoicing, or other financial/transactional systems is a strong plus. Hands-on experience using AI assistants and/or agentic workflows to improve engineering productivity is a plus. Benefits It is important for us to create a healthy, diverse, fun, and creative working environment, so besides all the basic benefits, we also focus a lot on social activities, flexible working hours and a good work-life balance. Flexible Work Environment : Enjoy a collaborative, inclusive, and open workplace designed to fit your needs and support work-life balance. Competitive Package : A competitive salary, an 11% company pension plan, and a comprehensive benefits package. Time to Recharge : Benefit from 32 paid vacation days (5 weeks + 5 extra) and paid parental leave to focus on what matters most. Career Growth : Access professional development opportunities and grow your career in a high-impact, high-growth industry. Stay Energized : Enjoy excellent coffee, tea, free snacks, and subsidized lunches at the office. Stay Active : Use our Spirii gym and shared company car to keep moving. Make an Impact : Be part of a team driving the future of sustainable energy while working on meaningful projects. Two innovation days per month for YOU to choose what you work on. The position is a permanent position in Copenhagen, Denmark. Danish language is not a requirement, but fluent English language skills are required. About Spirii – Who We Are Spirii is a full-service e-Mobility provider, which offers hardware and software charging solutions to companies in the private and the public sector. Spirii has recently celebrated its six-year anniversary as a founded company; however the people in Spirii have extensive experience working with electric cars and charging, as well as the development of future transport and energy systems. Spirii is an equal opportunity employer. We encourage applications from candidates of all backgrounds and experiences. Spirii strives to create an inclusive and diverse workplace, and we encourage all qualified applicants to apply regardless of age, gender, race, sexual/religious orientation, or disability.