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 stackFrontend 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 rigorously.
Strong 3D graphics engineering with Three.js / WebGL: scene, camera & projection math, raycasting/picking, mesh/BufferGeometry processing, render-loop performance.
Fluency in React + TypeScript
Backend competence in Node/TypeScript + relational SQL: NestJS or similar, PostgreSQL, transactions, concurrency.
Mathematical & geometric literacy: enough to understand theoretical concepts, read algorithmic code and research papers.
Product-minded and comfortable owning an under-documented, reverse-engineered problem space.

Strong bonus

BIM / CAD domain knowledge: IFC schema & STEP, architectural concepts (storeys, slabs, wall construction).
Geospatial / GIS: UTM/EPSG zones, GeoJSON, coordinate transforms.
Computer Vision: classical CV, deep learning segmentation.
Building physics: heat transfer, thermal bridging, U-values, hygrothermal behavior.
Real-time collaborative editing: optimistic concurrency, CRDT-adjacent sync, undo/redo, WebSocket reconciliation.
German language skills C1+.

What makes it a good role

Small and ambitious team, high ownership, a genuinely hard problem and a rare chance to do serious work at the pace AI-assisted development makes possible.
We're already an AI-first team: the tooling, conventions, and dense in-code documentation are built around that workflow, so you'll be productive in a deep domain far faster than the domain would normally allow.

Realistic profile: A strong TypeScript/3D engineer with excellent judgment and a proven AI-assisted workflow, who can grow into the BIM/geospatial specifics or someone from CAD/BIM/GIS who's a sharp reviewer and eager AI adopter. You don't need to tick every box; tell

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