(Senior) Full-Stack Engineer (AI-Assisted 3D / CAD / BIM Development) // 20° GmbH

About the product Buildings account for 35% of green house gas emissions in the EU. To accelerate the transition down to zero, we build browser-based SaaS for the German building-energy-renovation market. Our product pulls a real building from cadastral LOD2 data, floor plans and facade photos, reconstructs it as a clean, editable 3D model in the browser, and exports it to industry formats for downstream energy calculations and grant applications. It's a technically deep product: a versioned, real-time-capable, multi-user 3D building editor backed by a purpose-built geometry and computer vision engine. Much of the hardest code was and will be produced with agentic AI tooling under close human direction and review. We're looking for someone who works the same way. How we work We use agentic coding tools as the primary way we produce and change code, including in specialized domains: 3D geometry, computer vision, numerical optimization, format reverse-engineering. That means the human skill we hire for are:

• Decomposition & specification: turning hard, fuzzy problems into clean specs an AI agent can execute, in the right-sized steps.
• Review & verification: reading AI-generated code critically, especially algorithmic and numerical code, and proving to yourself it's correct (test design, edge cases, visual/geometric validation) rather than trusting it right away.
• Steering & taste: keeping an AI-built codebase coherent: enforcing our architecture conventions, catching plausible-but-wrong solutions, and knowing when to stop the agent and think.

You should already be doing this, or be visibly eager to. If your instinct is "I'd rather hand-write everything myself," this isn't the right fit. The stack Frontend Vite · React 18 · TypeScript · Zustand · Three.js · WebGL Backend NestJS · TypeScript · PostgreSQL · Supabase · Socket.io · OpenCV What you'll do

• Extend the 3D/CAD editor: new element types (windows/openings, rooms, zones, HVAC), multi-storey support, richer editing tools.
• Build out real-time multi-user collaboration
• Improve and verify the geometry engine and the IFC / CAD exporters: reconstruction quality, normalization, export fidelity.
• Own features across the full slice: Postgres schema → NestJS domain → REST/WS API → React/Three.js UI.

Essential

• High quality standards: while moving fast, you still care deeply about code quality and architectural soundness of the product.
• Fluency with AI-assisted / agentic development: hands-on experience driving tools like Claude Code to build real, non-trivial features, plus the discipline to review and verify their output rig