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Principal Software Engineer

United States, Washington, Redmond💼 Full-time🗓 2026-08-04 → 2026-09-26

Core

Designing and training relevance models (LLM fine-tuning, LTR) and building evaluation pipelines to improve Copilot Chat, Copilot Search, and BizChat experiences.

Role type

Principal Applied Scientist / Senior IC Machine Learning Engineer

Builds

Scalable retrieval, ranking, and semantic search solutions for enterprise Copilot systems

Domain

Enterprise AI, Search, Natural Language Processing, Information Retrieval

Deliverable

production ML models

Required skills

LLM fine-tuning, Learning-to-Rank (LTR), offline metrics design, online A/B experimentation, hypothesis formulation, scalable solution delivery, data analysis at scale, log/telemetry analysis, large dataset management, PyTorch, TensorFlow, scikit-learn, Hugging Face Transformers, Python, Java, C++, C#, JavaScript

Preferred skills

Statistical modeling, predictive analytics, research methodology, cross-functional collaboration, technical strategy translation

Technologies

PyTorch, TensorFlow, scikit-learn, Hugging Face Transformers

Responsibilities

Design and train relevance models using LLM fine-tuning and LTR approaches; Build robust evaluation pipelines using offline metrics and online A/B testing; Lead end-to-end applied science projects from ideation to shipping; Identify search/relevance gaps and formulate innovative hypotheses; Translate business goals into data-driven scientific strategies; Document and share experimental results and methodologies

Seniority

Principal, hands-on IC with strategic leadership

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