Mobile / Web Developer Intern for AI Spatial Products

Join sizeless (YC S23) — Building the Data Layer of the Built World

At sizeless, we turn smartphone videos into high-accuracy digital twins of buildings and infrastructure — no special hardware needed. Our 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.

We’re a small, high-energy, YC-backed team delivering outsized impact. Work directly with our 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
You’ll work directly with our CTO on the mobile capture and 3D visualization pipeline: turning smartphone video into reliable, structured spatial data that architects, engineers, and energy consultants can actually use. This is applied computer vision and 3D reconstruction with immediate real-world impact.

What you’ll do:

• Build and improve the mobile capture experience: reliable video acquisition, smooth scanning, error handling, and real-time feedback.
• Optimize processing pipelines: reconstruction, feature tracking, and 3D model generation.
• Work with CV & 3D geometry: tracking, depth estimation, and analytics.
• Contribute to the web-based 3D Viewer: Three.js / WebGL implementation, interactive tools, and UX improvements.
• (Optional/bonus) Collaborate with the AI/algorithm team to integrate new features or enhancements from the research side.

Who You Are

• You have experience in mobile or web development (React / iOS preferred)
• You have strong problem-solving skills and curiosity for applied computer vision, 3D reconstruction, or spatial computing
• You enjoy building end-to-end solutions and taking ownership
• Bonus: Experience with 3D visualization, Three.js/WebGL, or AR/Spatial apps
• You thrive in small teams, fast iteration, and high-impact environments

What We Offer

• Work directly with the founders & CTO, influencing core product and architecture
• Tackle unique technical challenges in CV, 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
• Flexible work arrangements, autonomy, and a learning-first culture

If AI, 3D tech, and real-world problem solving excite you, come build the data layer of the built world with us.