Senior Software Engineer

Senior Software Engineer – .NET/Azure Tax Platform

Amsterdam | Hybrid Work Model | Full-Time

Build software professionals trust when accuracy matters most.

Nextens develops the leading tax and compliance platform for professionals in the Netherlands. Trusted by thousands of experts, our software supports more than 1 million filings each year and helps organizations navigate evolving tax rules, high-volume data, and complex workflows with precision and reliability.

Built on deep domain expertise and a commitment to continuous innovation, Nextens not only ensures compliance, we set the standard for how tax professionals work.

As a Senior Software Engineer at Nextens, you own meaningful parts of a business-critical platform used daily by thousands of professionals. You design and deliver robust software, make sound technical choices, and help raise the quality of a platform where accuracy, reliability, and maintainability truly matter.

You enjoy complex engineering challenges and bring the judgement to balance quality, delivery, and long-term maintainability. Together with domain experts, fellow engineers, and product owners, you translate changing fiscal requirements into software our customers can trust completely.

You will join Team Fiscal, a product engineering team responsible for key parts of our Dutch tax filing platform. Together with fiscal experts and product colleagues, the team translates changing legislation into reliable software for tax professionals across the Netherlands.

• Design, build, and evolve core modules for tax filing and compliance, taking ownership from solution design through long-term maintainability.
• Use modern engineering practices, including AI-assisted development tools where appropriate, to improve productivity, quality, and maintainability.
• Develop and improve back-end and front-end components, APIs, interfaces, and integrations for a scalable, stable platform with large data volumes and complex tax logic.
• Contribute to new features and innovations, such as integrations with external systems and tools for tax advisory workflows.
• Work closely with domain experts and product owners to translate regulations and customer needs into reliable software solutions.
• Improve engineering quality through testing, refactoring, code reviews, and mentoring other engineers.

• A bachelor’s degree in Computer Science, Software Engineering, or equivalent experience.
• 4+ years of hands‑on software development experience, with evidence of increasing technical ownership, preferably with C#, .NET, Azure, and modern web technologies.
• A strong quality mindset, including testing, refactoring, code reviews, clean architecture principles, and coaching others to raise engineering standards.
• Interest in using AI‑assisted development tools responsibly as part of everyday engineering work.
• Strong analytical and problem-solving skills, especially when working with complex logic or data.
• A collaborative mindset — you enjoy working closely with engineers and domain experts to create practical, high‑quality solutions.
• A focus on clean, maintainable code and a habit of writing tests to ensure quality.
• Fluency in English is required. You can read and understand Dutch requirements texts; spoken Dutch is helpful but not essential.

At Nextens, your work powers the backbone of professional Dutch tax processing and helps thousands of professionals work smarter, faster, and more confidently. Our customers trust us not only for accuracy and compliance, but also because we innovate and improve how they work.

• Technical challenges → scalable systems, evolving regulations, and high-volume data processing.
• Real impact → your solutions directly support over 1 million filings every year.
• Ownership → take responsibility for important platform areas and help guide technical choices.
• Technical leadership → mentor colleagues and help raise engineering quality across the team.

• Hybrid flexibility → combine working from home with collaboration at our modern Amsterdam office.
• Work-life balance → flexible hours, generous vacation days, and up…