Principal Software Engineer

About the role

As a Principal Software Engineer, you’ll deliver mission-critical innovations that directly improve Copilot experiences. You’ll work on adapting advanced vector search algorithms (e.g., FAISS, ANN, ScaNN) for enterprise-scale semantic retrieval, improving classic and neural keyword search quality through deep language understanding, designing and training relevance models (including LLM fine-tuning and learning-to-rank approaches), and building robust evaluation pipelines using offline metrics and online A/B experimentation. This role requires driving cross-org collaboration with platform partners, applied science teams, and product teams across time zones.

Microsoft fosters a culture driven by growth mindset, collaboration, and inclusive innovation, rooted in core values of respect, integrity, and accountability. The company’s mission is to empower every person and every organization on the planet to achieve more.

Responsibilities

• Drive end-to-end applied science projects: from ideation and design to implementation, experimentation, and shipping. Lead high-impact projects that improve Copilot Chat, Copilot Search, and BizChat experiences by identifying search and relevance gaps, formulating hypotheses, and delivering scalable solutions.
• Innovate with scientific rigor: invent and apply cutting-edge techniques in machine learning, natural language processing, and information retrieval to address real-world challenges at enterprise scale. Design novel approaches for improving retrieval, ranking, query understanding, and semantic search in Copilot systems.
• Document, share, and amplify learnings: promote transparency and innovation by capturing experimental results, documenting methodology, and publishing internal learnings to enable broader impact across the organization.
• Translate business goals into scientific strategy: partner with product and business stakeholders to align team efforts with high-priority objectives. Translate ambiguous product requirements into clear, data-driven, and technically feasible directions.
• Collaborate across organizations and time zones: work cross-functionally with platform engineering teams, peer science orgs, and product managers to ensure alignment, resolve dependencies, and unblock progress. Serve as a key bridge between applied science innovation and product delivery.

Qualifications

Required Qualifications

• Bachelor's Degree in Computer Science or related technical field AND 8+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR equivalent experience.

Preferred Qualifications

• Bachelor's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 10+ years related experience (e.g., statistics, predictive analytics, research) OR
• Master's Degree in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 10+ years related experience (e.g., statistics, predictive analytics, research) OR
• Doctorate in Statistics, Econometrics, Computer Science, Electrical or Computer Engineering, or related field AND 10+ years related experience (e.g., statistics, predictive analytics, research) OR equivalent experience.
• 10+ years of industrial programming experience in modern languages such as Python, Java, C++, or C#, including production-level ML pipelines.
• Demonstrated expertise in data analysis at scale, including working with logs, telemetry, and large datasets to uncover behavioral patterns, build evaluation datasets, and derive insights.
• Familiarity with modern machine learning and deep learning frameworks such as PyTorch, TensorFlow, scikit-learn, and Hugging Face Transformers.
• Proven ability to collaborate across engineering, product, and science organizations and communicate technical details clearly to both technical and non-technical stakeholders.

Pay

The typical base pay range for this role across the U.S. is USD $165,600 - $296,400 per year. A different range applies to specific work locations, including the San Francisco Bay area and New York City metropolitan area, where the base pay range is USD $220,800 - $331,200 per year. Certain roles may be eligible for benefits and other compensation.