Principal Software Engineer

Microsoft Microsoft · Big Tech · Tokyo, Tokyo, Japan · Software Engineering

Principal Software Engineer for Microsoft Copilot's animated AI companion, Mico. This role involves technical leadership for a consumer-facing AI product, focusing on architecture, scaling, and the integration of 3D rendering, LLMs, memory systems, and personalization across multiple platforms. Responsibilities include owning system architecture, LLM orchestration, memory systems, personalization frameworks, and ensuring performance, reliability, and observability for millions of users.

What you'd actually do

  1. Own the end-to-end system architecture for the Mico experience, spanning 3D rendering (Picasso stack / Babylon Native), real-time character animation, lip-sync, locomotion, and expression systems.
  2. Design and evolve the LLM orchestration layer that powers Mico’s conversational intelligence, including prompt management, skill routing, and context window optimization.
  3. Architect the long-term memory system (Cosmos DB) — defining schemas, event handling, message partitioning, and retrieval strategies that enable Mico to remember and adapt to each user.
  4. Drive the adaptive personalization framework that governs how Mico adjusts behavior, tone, and interaction patterns based on user history and preferences.
  5. Architect solutions that work consistently across CMC (web), iOS, Android, and Windows surfaces, defining shared rendering abstractions and platform-specific optimizations.

Skills

Required

  • computer science or a related technical discipline
  • 8 years of engineering experience
  • C++
  • C#
  • Java
  • JavaScript
  • Python
  • iOS development
  • Android development
  • full-stack engineering
  • consumer product development
  • lead through influence
  • technical direction for teams
  • architecture reviews
  • design sprints
  • technical alignment sessions
  • AI product development
  • integrating AI into daily development processes
  • English speaking

Nice to have

  • automated evaluation pipelines for 3D animation fidelity, lip-sync accuracy, expression transitions, and locomotion smoothness
  • mobile E2E test coverage
  • staging environment fidelity
  • quality gates in CI/CD pipelines
  • security posture for Mico systems
  • S360 compliance
  • resource ownership audits
  • data classification for user memory and personalization data

What the JD emphasized

  • hundreds of millions of users
  • consumer scale
  • consumer AI experiences
  • consumer product development
  • AI products

Other signals

  • shipping to hundreds of millions of users
  • building foundational technology
  • real-time 3D rendering, large language models, and personalized experiences at consumer scale
  • technical leadership across the full Mico engineering stack
  • drive architecture decisions
  • set the engineering quality bar
  • lead a globally distributed team
  • building and scaling one of Microsoft’s most visible consumer AI experiences
  • Picasso rendering engine
  • cross-platform animation delivery
  • LLM orchestration
  • long-term memory systems
  • adaptive personalization framework
  • end-to-end system architecture
  • real-time character animation, lip-sync, locomotion, and expression systems
  • LLM orchestration layer
  • prompt management, skill routing, and context window optimization
  • long-term memory system
  • adaptive personalization framework
  • work consistently across CMC (web), iOS, Android, and Windows surfaces
  • asset pipeline
  • Performance, Reliability, and Observability
  • millions of daily active users
  • low-latency rendering
  • efficient asset delivery via CDN
  • graceful degradation on low-end devices
  • robust error recovery
  • observability dashboards
  • monitor Mico engagement, conversation duration, animation frame rates, and error rates
  • design controlled flights and ablation experiments
  • interpret telemetry
  • use data to guide decisions
  • extensive expertise in iOS and/or Android development
  • strong full-stack engineering capabilities
  • comprehensive knowledge of consumer product development
  • lead through influence
  • establishing technical direction for teams
  • conducting architecture reviews, design sprints, and technical alignment sessions
  • Solid background in AI, including hands-on experience developing AI products or integrating AI into daily development processes.