New job, posted less than a week ago!
Job Details
Posted date: Jan 22, 2026
There have been 2367 jobs posted with the title of Principal Software Engineer all time at Microsoft.There have been 2367 Principal Software Engineer jobs posted in the last month.
Category: Software Engineering
Location: Geneva, Geneva
Employment type: Full-Time
Work location type: 0 days / week in-office – remote
Role: Individual Contributor
Description
OverviewMicrosoft 365 Copilot is transforming productivity by integrating large language models with user data, Microsoft Graph, and the web. At the core of this innovation is the Substrate Intelligence Platform (DSX) team, which powers personalized, secure, and scalable Copilot experiences across Microsoft 365—Teams, Word, Excel, PowerPoint, OneNote, and beyond.
Our team is pioneering the infrastructure for tenant‑isolated fine‑tuning, a foundational platform capability that enables customers to safely personalize Copilot agents using their own data. This includes support for leading OpenAI models (e.g., GPT‑5, O4 Mini) and open‑source models such as Qwen, Mistral, and GPT‑OSS.
We own the end‑to‑end fine‑tuning platform via Heron, spanning:
Data extraction and isolationSecure training and evaluation workflowsModel deployment, migration, and lifecycle managementOur systems operate at massive scale in multi‑tenant environments, enforce strict security and compliance boundaries, manage shared GPU resources effectively, and enable seamless onboarding of new models and customers.
As a Principal Software Engineer, you will play a critical technical leadership role in shaping the next generation of Copilot’s fine‑tuning and evaluation infrastructure.
This role goes beyond feature development. You will:
Set technical direction for core platform componentsInfluence architecture and design decisions across multiple teamsTackle ambiguous, high‑impact problems at the intersection of AI infrastructure, security, scale, and reliabilityEnable Copilot scenarios that directly unlock new customer value and revenueYou will collaborate deeply with partner teams across Azure Machine Learning, Foundry, Singularity, TCaaS (Tenant Copilot as a Service), Heron Infra, Copilot Inferencing, and Security & Compliance, driving alignment on data movement, isolation models, quota management, GPU fungibility, and model deployment strategies.
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.
Responsibilities
Architect and lead the design of large‑scale, distributed services that power tenant‑isolated fine‑tuning and evaluation workflows.Drive end‑to‑end technical ownership of critical platform areas, from data ingestion and training orchestration to deployment, rollback, and monitoring.Define and evolve secure data movement patterns across tenant boundaries, ensuring compliance with Microsoft security, privacy, and governance requirements.Establish long‑term technical vision and roadmap for the Heron fine‑tuning platform, balancing scalability, reliability, cost, and developer velocity.Lead cross‑team technical reviews, influencing designs and driving alignment across multiple organizations.Build frameworks and abstractions that improve operational excellence, including observability, quota management, failure recovery, and developer ergonomics.Act as a technical mentor for senior and junior engineers, raising the bar on design quality, code health, and engineering rigor.Partner with engineering managers and product leaders to translate business goals into executable technical strategies.Proactively identify and resolve systemic production issues, driving durable fixes rather than tactical mitigations.
Qualifications
Required Qualifications:
Bachelor's Degree in Computer Science or related technical field AND hands on technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or PythonOR equivalent experience. Proven experience designing and operating large‑scale distributed systems in production.Demonstrated ability to lead technical decisions across multiple teams or services.Other Requirements:
Ability to meet Microsoft, customer and/or government security screening requirements are required for this role. These requirements include but are not limited to the following specialized security screenings:Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter.
Preferred Qualifications:Master'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 PythonOR Bachelor's Degree in Computer Science or related technical field AND extensive technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python OR equivalent experience. Experience building platform or infrastructure services in cloud environments (Azure preferred).Deep understanding of multi‑tenant architectures, security boundaries, and privacy‑compliant system design.Hands‑on experience with Azure Machine Learning, Kubernetes, GPU‑backed workloads, or large‑scale data pipelines.Track record of driving architecture simplification, reliability improvements, and cost efficiency at scale.Ability to operate effectively in high ambiguity, influencing without authority and earning trust across org boundaries.
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.
Check out other jobs at Microsoft.