Sr Fullstack Javascript Developer

As part of our interview process and our commitment to building high-performing teams, we've partnered with The Culture Index Program to better understand work styles and team dynamics. To support this process, we kindly ask you to complete a brief survey as part of the application process when submitting your profile. It should take no more than 7 minutes, and there are no right or wrong answers. We appreciate your participation and look forward to learning more about how you might fit within our team! Culture Index Survey: https://go.cultureindex.com/p/weJLJlIGZ2DauZkoW Collectivus Holdings guides many of the most prestigious brands in the Collecting, Trading Card Game, and Hobby industries. With a century's worth of collective experience in driving product and service innovation, high-end quality standards, and elevated customer experience, Collectivus brands are among the most recognized and loved throughout the world by the communities they serve. Website: https://www.collectivusholdings.com Locations: Aarhus - Dallas - Delhi - Lisbon - Nashville - Worldwide Title: Senior Full-Stack JavaScript Developer (Node.js / NestJS / Next.js) Job Location: Remote - US We are seeking a Senior Full-Stack JavaScript Developer (Node.js / NestJS / Next.js) to take technical ownership of both backend and frontend architecture. This role focuses on building and maintaining scalable, secure, and high-performance web applications using Node.js, NestJS, and Next.js. You will work with a high degree of autonomy, collaborate closely with product, frontend, and infrastructure teams, and help set engineering standards while mentoring junior developers. Key Responsibilities: Design, develop, and maintain backend services using Node.js, NestJS, and TypeScript Build, document, and optimize RESTful APIs and integrate third-party services Develop and maintain frontend applications using Next.js Design and optimize PostgreSQL schemas, queries, and migrations Define and maintain API contracts between frontend and backend systems Ensure platform security, performance, scalability, and reliability Conduct code reviews, enforce best practices, and mentor junior developers Participate in system architecture decisions and technical design discussions Troubleshoot, debug, and resolve production issues Manage deployments and support applications on Linux/Ubuntu server Maintain technical documentation and source control using Git/bitbucket Qualifications: 5+ years of professional experience with Node.js Strong hands-on experience with NestJS and TypeScript Solid experience building frontend applications with Next.js Strong understanding of HTTP, authentication, sessions, and web security best practices Hands-on experience with PostgreSQL, including schema design and query optimization Proven experience building and maintaining production-grade APIs Comfortable working in Linux/Ubuntu environments Strong knowledge of Git workflows, debugging, and testing Ability to work independently and take end-to-end technical ownership Strong problem-solving skills and attention to detail Nice to Have (Optional) Experience with containerization (Docker) and CI/CD pipelines Familiarity with cloud platforms (AWS, GCP, or Azure) Experience with background jobs, queues, or event-driven systems Exposure to monitoring, logging, and observability tools Prior experience mentoring or leading small engineering teams #LI-Remote