We at Holycode are currently looking for a passionate and experienced Mobile / Web Developer to join sizeless (https://sizeless.co/) , a YC S23-backed startup building the data layer of the built world. About the company Sizeless (https://sizeless.co/) turns smartphone videos into high-accuracy digital twins of buildings and infrastructure — no special hardware needed. Their mission: digitize the built world and provide a unified data layer that empowers architects, engineers, and energy consultants to make smarter, faster decisions — unlocking new insights and AI-driven applications. They are a small, high-energy, YC-backed team delivering outsized impact. You will work directly with their founder & CTO, push the boundaries of computer vision and 3D reconstruction, and spatial intelligence. All roles tackle the same core challenge: turning smartphone video into reliable, structured spatial data. You’ll Work On They are looking for a Mobile / Web Developer to help build and scale their mobile capture experience and 3D visualization stack. You will work on production systems that turn real-world environments into usable digital building data. This role sits at the intersection of mobile development, web front-end, and 3D visualization. While you will interface with computer vision and spatial data, the focus is on product, UX, and reliable delivery. Your Profile + Strong experience in mobile or web development (iOS / Swift and/or modern web frontend) + Solid frontend fundamentals and product-oriented thinking + Experience with or strong interest in 3D visualization (e.g. Three.js, WebGL, interactive 3D UIs) + Comfortable working with complex datasets and performance-sensitive applications + You enjoy ownership, fast iteration, and working in small, high-impact teams Bonus: + Experience with spatial applications, AR, or 3D viewers + Exposure to geometry, mapping, or visualization-heavy products   Key Responsibilities + Build and improve the mobile capture experience (iOS), including: reliable video acquisition, smooth scanning flows, error handling and real-time user feedback + Contribute to processing and visualization pipelines, integrating reconstructed geometry and large spatial datasets + Develop and extend the web-based 3D Viewer using Three.js / WebGL + Implement interactive tools such as camera controls, measurements, and UX improvements + Collaborate closely with backend and algorithm teams to integrate new features into production + Ensure performance, usability, and reliability across devices + Take ownership of features through implementation, deployment, and iteration + (Optional) Collaborate with the AI / algorithm team to integrate new spatial or geometry-related capabilities into the product   Why you will love working here + Tackle unique technical challenges in computer vision, 3D reconstruction, and spatial intelligence + Be part of a small, high-impact team backed by Y Combinator and world-leading investors + Shape the future of digital twins and spatial data for buildings + Familial working atmosphere in an open-minded multinational team + Working remotely (from Romania) + All necessary equipment – up to you to decide what you prefer + A budget for professional improvement (courses, conferences, books) + A budget for multi-benefits platform (meal tickets, private pension, etc.) + Premium private medical subscription with nationwide coverage + Budget for mastering English and German + Skilled and senior co-workers + Opportunities to build products that really make a difference + Opportunities to learn and grow with us   If you are looking for an environment where you can grow professionally, work on technically challenging problems, and build real-world AI products with impact, please submit your CV in English. Powered by JazzHR