Mico is the animated AI companion at the heart of Microsoft Copilot — a 3D character with expressive animations, lip-sync, voice interaction, long-term memory, and adaptive behavior, shipping to hundreds of millions of users across web (CMC), iOS, Android, and Windows. We are building foundational technology that merges real-time 3D rendering, large language models, and personalized experiences at consumer scale.

As a Principal Software Engineer, you will provide technical leadership across the full Mico engineering stack. You will drive architecture decisions, set the engineering quality bar, and lead a globally distributed team spanning the US, Japan, and China (STCA) in building and scaling one of Microsoft’s most visible consumer AI experiences. You will be responsible for the Picasso rendering engine, cross-platform animation delivery, LLM orchestration, long-term memory systems, and the adaptive personalization framework that makes Mico feel alive.

Microsoft’s mission is to empower every person and every organization on the planet to achieve more. As employees we come together with a growth mindset, innovate to empower others, and collaborate to realize our shared goals. Each day we build on our values of respect, integrity, and accountability to create a culture of inclusion where everyone can thrive at work and beyond.

• 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.
• Design and evolve the LLM orchestration layer that powers Mico’s conversational intelligence, including prompt management, skill routing, and context window optimization.
• 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.
• Drive the adaptive personalization framework that governs how Mico adjusts behavior, tone, and interaction patterns based on user history and preferences.
• Architect solutions that work consistently across CMC (web), iOS, Android, and Windows surfaces, defining shared rendering abstractions and platform-specific optimizations.
• Coordinate Unified UI integration — ensuring Mico’s visual presence (header, footer, composer, snap-to positioning) works seamlessly with the Copilot shell across all form factors.
• Own the asset pipeline: CDN-delivered 3D models, video backgrounds, animation configs, and per-surface configuration files (e.g., mico_config_cmc.json, mobile configs).
• Performance, Reliability, and Observability:
• Design systems for millions of daily active users — low-latency rendering, efficient asset delivery via CDN, graceful degradation on low-end devices, and robust error recovery.
• Build and maintain observability dashboards using Azure Data Explorer (Kusto) to monitor Mico engagement, conversation duration, animation frame rates, and error rates across surfaces.
• Partner with data science to design controlled flights and ablation experiments, interpret telemetry, and use data to guide decisions.

Required Qualifications:

• Bachelor’s degree in computer science or a related technical discipline, along with at least 8 years of engineering experience, including proficiency in programming languages such as C++, C#, Java, JavaScript, or Python.
• Extensive expertise in iOS and/or Android development; strong full-stack engineering capabilities with comprehensive knowledge of consumer product development.
• Demonstrated ability to lead through influence, establishing technical direction for teams of 3–10 engineers across US, Japan, and China time zones. Experienced in 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.
• Speaking English is required for daily work.

Preferred Qualifications:

• Ability to establish automated evaluation pipelines for 3D animation fidelity, lip-sync accuracy, expression transitions, and locomotion smoothness — a frontier challenge unique to character AI.
• Ability to drive mobile E2E test coverage and improve staging environment fidelity, so issues are caught before production.
• Ability to define and enforce quality gates in CI/CD pipelines, ensuring regressions in animation rendering, voice interaction, and Mico Moments content delivery are caught automatically.
• Ability to own the security posture for Mico systems — S360 compliance, resource ownership audits, and data classification for user memory and personalization data.

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This position will be open for a minimum of 5 days, with applications accepted on an ongoing basis until the position is filled.

Microsoft is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to age, ancestry, citizenship, color, family or medical care leave, gender identity or expression, genetic information, immigration status, marital status, medical condition, national origin, physical or mental disability, political affiliation, protected veteran or military status, race, ethnicity, religion, sex (including pregnancy), sexual orientation, or any other characteristic protected by applicable local laws, regulations and ordinances. If you need assistance with religious accommodations and/or a reasonable accommodation due to a disability during the application process, read more about requesting accommodations.