Senior Full-Stack & AI Engineer

Company Description Kupyo is a marketplace app that merges video content with classified advertising, enabling users to buy and sell items through engaging video listings. The platform uses AI to improve listing quality, streamline discovery, and support more meaningful buyer-seller interactions. By pairing short-form video with intelligent features, Kupyo aims to redefine how people shop and sell online. The team focuses on creating a seamless, intuitive experience that makes transactions faster, safer, and more enjoyable for everyone.Role Description This is a full-time, on-site Senior Full-Stack & AI Engineer role based in Zagreb. In this position, the engineer will design, develop, and maintain end-to-end features for Kupyo’s video-first marketplace, including front-end interfaces and back-end services. Daily responsibilities include building scalable APIs, integrating and optimizing AI models for video and listing enhancement, and ensuring high performance and reliability of the platform. The engineer will collaborate closely with product, design, and mobile teams to define technical requirements, review code, and drive best practices in software architecture and data security. The role also involves monitoring production systems, resolving issues, and continuously improving the platform’s functionality and user experience.Qualifications Strong proficiency in modern front-end and back-end development (e.g., TypeScript/JavaScript, React or similar frameworks, Node.js or comparable server-side technologies).Experience with AI and machine learning tools and workflows (e.g., model integration via APIs, recommendation systems, computer vision or NLP for content and video analysis).Solid background in databases and cloud infrastructure (e.g., SQL/NoSQL databases, cloud platforms such as AWS, GCP, or Azure, containerization, CI/CD pipelines).Demonstrated skill in building scalable, secure, and high-availability systems for consumer-facing applications.Proficiency in software engineering best practices, including testing, code review, documentation, and version control (Git).Excellent problem-solving abilities and communication skills, with a collaborative mindset in cross-functional teams.Several years of experience in full-stack engineering, including senior-level responsibility for architecture or technical leadership.Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field, or equivalent practical experience.Experience with video processing, streaming technologies, or marketplace platforms is an advantage.Comfort working on-site in Zagreb and contributing to a fast-paced startup environment.