Principal Researcher

Join the team that powers one of the most heavily used and most visible capabilities in Windows: Search. As Windows evolves into an agent-first, AI-powered operating system, Search is becoming the primary discovery, reasoning, and grounding layer across user journeys and agentic experiences. The Windows Search and AI Platform team is responsible for building the core Search, indexing, and semantic understanding infrastructure that serves more than a billion users worldwide.  This role is for a  Principal Researcher  with deep prior Search experience who will define and drive the architectural direction of Windows Search and related semantic systems, spanning indexing, retrieval, ranking, reliability, and AI-powered experiences.  As a Principal Researcher on Windows OS Search, you will define the long-term technical vision for Windows Search and semantic retrieval systems and building graph data across systems. You will work across engineering, product, and partner teams to ensure Search is reliable at scale, measurable through quality signals, and extensible for future agentic scenarios.  We are seeking a visionary and hands-on Principal Researcher to lead the next-generation intelligent search architecture for the Windows Operating System. In this role, you will bridge frontier AI research—spanning local Small Language Models (SLMs), NPU-accelerated dense retrieval, on-device vector indexes, and contextual temporal graphs—with low-level systems engineering.  You will redefine how over a one billion users discover, access, and interact with files, applications, cloud content, and system state, delivering sub-millisecond lexical and semantic search under strict power, memory, and zero-trust privacy constraints.  This role blends deep technical expertise in Search systems with cross-org architectural leadership and solid engineering judgment.  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.

Research & Architectural Roadmap: Define the multi-year vision for Windows OS search, context-aware indexing, semantic file retrieval, and OS-level neural search systems.  On-Device AI & NPU Optimization: Design, adapt, and compress state-of-the-art SLMs and embedding models (via quantization, pruning, and distillation) for local execution on NPUs, GPUs, and CPUs via frameworks like ONNX Runtime/DirectML.  Core OS & Storage Integration: Architect low-latency vector indexing structures and hybrid search rankers integrated into the OS file system and runtime, ensuring minimal system memory footprint and battery drainage.  Contextual & Semantic Graph Retrieval: Design algorithms that synthesize user activity context, application telemetry, and semantic relationships without compromising user privacy or shipping raw data off-device.  Zero-Trust & Local Privacy: Guarantee zero-trust computational isolation where search indexing, embedding generation, and contextual ranking remain strictly on-device.  Cross-Disciplinary Leadership: Partner closely with Core OS Systems Engineering, Hardware Acceleration Teams, Silicon Partners (Intel, AMD, Qualcomm), and Product UX teams to ship research innovations into production releases.  IP & Scientific Visibility: Drive strategic patent filings, publish in top-tier IR/AI venues, and mentor senior researchers and engineering leads across the division.  Define the long-term architectural direction for Windows Search, including indexing pipelines, retrieval systems, ranking, and semantic enrichment.  Serve as the research authority for Search-related design reviews, tradeoff discussions, and platform decisions.  Drive