Microsoft is a company where passionate innovators come to collaborate, envision what can be and take their careers further. This is a world of more possibilities, more innovation, more openness, and the sky is the limit thinking in a cloud-enabled world. Microsoft’s Azure Data engineering team is leading the transformation of analytics in the world of data with products like databases, data integration, big data analytics, messaging & real-time analytics, and business intelligence. The products our portfolio include Microsoft Fabric, Azure SQL DB, Azure Cosmos DB, Azure PostgreSQL, Azure Data Factory, Azure Synapse Analytics, Azure Service Bus, Azure Event Grid, and Power BI. Our mission is to build the data platform for the age of AI, powering a new class of data-first applications and driving a data culture. ​​Within Azure Data, the databases team builds and maintains Microsoft's operational Database systems. We store and manage data in a structured way to enable multitude of applications across various industries. We are on a journey to enable developer friendly, mission-critical, AI enabled operational Databases across relational, non-relational and OSS offerings.​ ​​Azure Cosmos DB is Microsoft's globally distributed, multi-model NoSQL database service. We are investing heavily in next-generation indexing and retrieval infrastructure to power AI-native workloads such as vector similarity search, hybrid search, and semantic retrieval. We are looking for a Principal Software Engineer to drive the architecture, design, and implementation of vector indexing and retrieval features in Cosmos DB. You'll collaborate with product, applied AI, and infrastructure teams to build high-performance, highly available vector search capabilities natively into Cosmos DB. ​​ We do not just value differences or different perspectives. We seek them out and invite them in so we can tap into the collective power of everyone in the company. As a result, our customers are better served. **Responsibilities** ​​Architect and lead development of scalable, distributed vector indexing features (e.g., DISKANN) within the Cosmos DB engine. Optimize storage and compute efficiency for vector search scenarios, including approximate nearest neighbor (ANN) algorithms. Partner with the AI/ML, Azure Cognitive Search, and OpenAI teams to integrate semantic search and hybrid retrieval capabilities. Drive technical design reviews, RFCs, and cross-team architectural alignment. Ensure robust telemetry, monitoring, and diagnostics are built into vector indexing components. Work closely with the product team to define roadmaps, goals, and success metrics for AI-native features in Cosmos DB. ​ Embody our culture (https://careers.microsoft.com/v2/global/en/culture) and values (https://www.microsoft.com/en-us/about/corporate-values) **Qualifications** Required/Minimum Qualifications 10+ years of experience in distributed systems, databases, or large-scale search infrastructure. Strong coding skills in C++, Rust, or C#, with deep systems-level expertise. Proven track record of designing high-scale, low-latency services in production. Solid understanding of storage engines, indexing, and retrieval models. Ability to mentor a team of senior engineers. **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/Additional Qualifications ​​Experience working on database internals (e.g., indexing, query execution). Exposure to AI/ML systems, LLM-driven search, or retrieval-augmented generation (RAG). Experience with cloud-scale services (Azure, AWS, or GCP). ​ \#azdat \#azuredata ​​\#cosmosdb #microsoftidc​ Microsoft is an equal opportunity employer. Consistent with applicable law, 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 and/or a reasonable accommodation due to a disability during the application process, read more about requesting accommodations (https://careers.microsoft.com/v2/global/en/accessibility.html) .