Senior Full-Stack Next.js / React Developer

We are looking for a highly experienced Senior Full-Stack Web Developer to take full technical ownership of our existing website af-doctors.de. Fluent German is required, as communication with our team and the current developer will be primarily in German. Our website is custom-built using Next.js, React, Node.js and AI-assisted development and currently runs on infrastructure managed by our existing developer. Initial Project You will handle the complete technical migration, including: Full Git repository and source-code transfer Migration to new A&F Doctors-owned hosting/server infrastructure Deployment and server configuration Environment variables, API keys and secrets DNS/domain configuration Databases, storage and external services Existing APIs and integrations Booking-system API integration Analytics, tracking, forms, email/SMTP and third-party services Testing and zero-downtime migration Full technical documentation Ongoing Work After migration, you should be able to: Maintain and further develop the website Build new features and pages Create and integrate APIs Improve UI/UX Improve performance, Core Web Vitals and SEO Optimize security and infrastructure Troubleshoot frontend, backend and server issues Use modern AI development tools efficiently Required Skills Strong expertise in: Next.js, React, JavaScript/TypeScript, Node.js, REST APIs, Git/GitHub, databases, hosting/server management, DNS, CI/CD, deployment, security and modern web architecture. Experience with AI-assisted coding tools such as Cursor, Claude Code, GitHub Copilot or similar is highly preferred. German language skills are mandatory. Please send: Examples of complex Next.js/React projects you personally worked on Your experience migrating custom applications between servers/developers Your experience with APIs and booking-system integrations Which AI coding tools you use Your German level Your availability for ongoing collaboration We are looking for a long-term technical partner, not just someone for a one-time migration.