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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Backend Developers - **Company:** NS Groep N.V. - **Location:** Utrecht, Netherlands - **Experience:** Expert - **Salary:** €6,240.0 - **Contract:** Contract - **Skills:** Clean Code Principles, Java (Programming Language), Application Programming Interfaces (APIs), Amazon Web Services, Business Logic, Acceptance Test-Driven Development, Microsoft Azure, Mobile Application Development, Cloud Computing, Cloud Engineering, Code Review, Continuous Integration, DevOps, Gradle, Mobile Application Software, Spring Framework, Node.Js, NoSQL, Pair Programming, Scrum Methodology, Rxjava, Software Construction, SQL Databases, TypeScript, Test-Driven Development (TDD), Spring-boot, Technical Debt, AWS Lambda, Backend, Git, Cloudformation, Kotlin, Kubernetes, AWS Fargate, Npm(Software), Front End Software Development, Serverless Computing, Docker, Service Stack, Legacy Systems, Microservices - **Published:** October 14, 2026 - **Apply:** https://www.werkenbijns.nl/vacatures/senior-backend-developer-team-map-utrecht-1344927/solliciteer ## About the Role You are a fast learner who enjoys continuous improvement and knows how to bring others along on that journey. Agile values such as collaboration, adaptability, and delivering value in short iterations fit naturally with your way of working. You have strong communication skills, show initiative, and are comfortable making decisions. You take ownership of the systems you build and operate, allowing you to react quickly to production incidents, identify the right solutions, and communicate clearly with stakeholders., * Extensive experience building and operating backend applications in production environments, using Java or Kotlin as your primary language. * Strong software craftsmanship practices, including Test-Driven Development (TDD), refactoring, and pair/mob programming, applied to both new and existing codebases. * Experience with cloud-based microservices and APIs running in containers and/or serverless environments, preferably on AWS. * A track record of helping teams and colleagues grow, for example through coaching, introducing standards, or leading technical initiatives across multiple teams. * Ownership of production systems, including CI/CD pipelines, monitoring, incident resolution, and clear stakeholder communication. * HBO or university-level working and thinking capabilities. * Strong communication skills in either Dutch or English., * TypeScript / Node.js * Spring WebFlux or RxJava * Infrastructure as Code (CDK, CloudFormation) * Kubernetes or AWS Fargate * SQL and NoSQL databases * Mobile app development, * A background screening, including a Certificate of Conduct (VOG), is part of the recruitment process. This also includes signing integrity and confidentiality agreements. ## Description * You get the unique opportunity to build the backend of the NS app and key components of NS.nl, serving over 4 million users every month. * You'll join a forward-thinking DevOps team with the freedom to contribute ideas and experiment with new technologies. * The teams are end-to-end responsible for the entire process: discovery, user research, design, development, and continuous delivery. We build, run, and host the app, web platforms, and backend APIs ourselves: "You build it, you run it, you love it." What you'll do as a Senior Backend Developer at NS As a Backend Developer, you will be responsible for further developing and maintaining the backend APIs that power the NS app and website. You'll build user-friendly features that meet the highest quality standards, such as improvements to the journey planner, booking flows, customer service functionality, personalization features, and integrations with mobility partners offering shared transportation services. You will work closely with business analysts, product owners, and solution architects to translate business and functional requirements into technical solutions. You will: * Develop structured, maintainable code and proactively tackle technical debt and legacy systems. * Help migrate services to our target cloud architecture. * Monitor applications and respond effectively to incidents and production disruptions. * Collaborate with other teams to make functionality available in the frontend (mobile app and web). * Contribute to architectural decisions and the implementation of complex business logic, much of which resides in the backend. * Drive improvements across team boundaries as one of the technical leaders within the backend community. During bi-weekly backend sessions, you introduce improvements and help ensure their adoption across all six teams. * Coach colleagues both inside and outside your team through pair programming, code reviews, and knowledge sharing. * Work test-driven, continuously refactor, and promote pair programming and mob programming as standard practices. This helps improve the quality and robustness of our APIs in both new and legacy code. * Work together with the Solution Architect to help define the roadmap for migration toward our cloud-native target architecture. Our Technology Stack Our backend primarily runs on Java/Kotlin with Spring Boot, complemented by Node.js Lambdas written in TypeScript, hosted on AWS using both containerized and serverless solutions. We work with: * Git * Gradle * NPM * Docker * Azure DevOps (CI/CD) Don't know every technology yet? No problem. You'll have plenty of opportunities to learn and grow with us. Hier ga je werken Based either at our headquarters next to Utrecht Central Station or from home, you'll join a multidisciplinary DevOps team typically consisting of: * 2 Android Developers * 2 iOS Developers * 2 Backend Developers * 2 Web Developers * UX/Visual Designer * Business Analyst * Tester * Scrum Master * Product Owner A Solution Architect provides guidance on the overall target architecture. Together, we brainstorm innovative solutions, collaborate intensively, and continuously push the boundaries of our craft. And of course, you'll spend most of your time doing what you love most: building software. We support your growth by providing access to the latest technologies and development practices. Your team will be one of six teams working together on the NS app and key components of NS.nl. Backend Developers from all teams meet every two weeks to showcase their work, exchange knowledge, and discuss cross-team improvements. These sessions provide a platform where you can make an impact and help shape future direction. Among developers, we foster a culture where every opinion matters and nothing is ever truly set in stone.