Senior / Lead Applied AI Engineer – AI Labs

About the role

On's AI Lab and Emerging Technology Incubation team explores, prototypes and builds frontier digital products and agentic systems that help people build a lasting relationship with movement. This Lead Software Engineer role anchors backend, data and applied-AI architecture across incubation ventures, combining early-stage product exploration with production-ready engineering. It reports to the Senior Lead - Staff Software Engineer for AI Labs and is a hybrid position, 3 days a week in the Zurich office, with relocation support.

Key responsibilities

• Navigate from ambiguity to production: lead backend, data and applied-AI architecture while contributing to frontend and mobile surfaces, shipping cohesive vertical slices.
• Partner with Product, Design and Research to turn early-stage hypotheses into domain models, technical RFCs and production applications.
• Design resilient AI and real-time systems: low-latency streaming runtimes, tiered agent memory, hybrid retrieval pipelines and programmatic evaluation frameworks.
• Build cloud-native (GCP, GKE), secure and observable foundations that scale into wider engineering clusters.
• Use frontier AI tooling and coding agents to explore new domains quickly, with strict type safety and maintainable code.
• Act as a technical partner across teams in Zurich, London and other stakeholders, shaping product direction and technical execution.

Required profile

• Proven experience building production-grade multimodal agentic systems (tiered agent memory, multimodal ingestion, RAG, real-time voice or streaming pipelines, tool integration protocols such as MCP, automated evaluation).
• Degree in Computer Science, Software Engineering or a related field, or equivalent practical experience.
• Track record in high-ambiguity environments with a product mindset, and experience with enterprise cloud infrastructure (GCP, GKE) and architectural RFCs.
• Collaborative mindset with Product, Design and Research; self-directed learner.

Required skills

• Python (FastAPI, Pydantic, asyncio) and/or TypeScript (NestJS)
• Relational and vector data modeling (PostgreSQL, pgvector), event-driven architectures and API design
• Experience scaling distributed backend systems; frontend/mobile (React, TypeScript, Flutter) or container infrastructure (Docker, Kubernetes) when needed
• Valued: real-time streaming runtimes (LiveKit, WebRTC, Gemini Multimodal Live, OpenAI Realtime, ElevenLabs) and familiarity with health, human movement or R&D incubation settings