Senior Product Engineer (m/f/d)

Headquarters: Berlin, Germany, Remote Journee is hiring a Senior Product Engineer About Ojin , by Journee Journee is a technology startup founded in 2020. Our in-house low-latency streaming technology and GPU fleet orchestration systems are the engines behind our award-winning work with brands such as BMW, H&M, and Siemens. We are now building and launching Ojin , a real-time generative AI platform for developers. Ojin provides the APIs and inference infrastructure for developers to build and scale interactive applications and AI agents. For this new venture, we are building a small, ambitious team of highly talented individuals. The Role As a Senior Product Engineer, you will not just write code—you will own products and features end-to-end. In the modern AI-accelerated landscape, we believe a single high-leverage engineer can drive impact comparable to entire teams of the past. You will be the bridge between technical implementation, product design, and user experience. We are looking for a builder who thrives in startup environments. You will work directly on Ojin, building everything from high-end interactive frontends to complex backend agentic systems. You won't just be handed a ticket; you will help define the solution, design the architecture, and ship it to users. This is a full-time position, either in our Berlin office or remote (CET +/- 2h). What You'll Do End-to-End Ownership: Drive features and projects from abstract concepts to production deployment. You will take ownership across UI/UX design, product logic, and technical implementation. Full-Stack Web Development: Architect and build our core web infrastructure using TypeScript, React, and Node.js. You will ensure our user-facing applications are responsive, intuitive, and robust. AI & Agent Systems: Develop and maintain Python backends for our AI capabilities, including proxy services, agentic systems, and conversational AI flows. Systems Architecture: Design scalable backend systems. While you wil