Top Principal Software Engineer Jobs in Los Angeles, CA

Lead the architecture, technical strategy, and roadmap for Microsoft's Windows ML compiler stack. Design high-performance compiler infrastructure, execution engines, optimization frameworks, and developer tools supporting CPU, GPU, and NPU workloads. Drive NPU enablement, graph optimization, scheduling, memory management, code generation, and hardware abstraction. Partner with silicon vendors and internal teams, influence AI hardware and platform strategy, lead cross-team initiatives, and mentor engineers developing on-device and generative AI capabilities.

Lead architecture, design, integration, and optimization of multithreaded embedded C/C++ software for Linux, RTOS, and bare-metal platforms supporting satellite communications. Define scalability, fault-tolerance, recovery, performance, and testing strategies; troubleshoot hardware and software; guide cross-functional technical decisions; and mentor senior engineers while delivering high-quality software for space and ground systems.

Lead development of Elasticsearch vector similarity search capabilities, including designing algorithms and data structures, implementing features, fixing bugs, and improving code quality. Collaborate asynchronously with a globally distributed engineering team and open-source community. Serve as a subject-matter expert on vector search relevance and implementation while contributing modern Java code and guiding cross-functional initiatives autonomously.

Work with customers and cross-functional teams to design, build, and deliver cloud-based solutions. Lead design, identify dependencies, mentor engineers, act as DRI and on-call, and improve availability, reliability, observability, and performance. Contribute to open-source assets and collaborate with Microsoft product teams to produce extensible, maintainable code and scalable solution patterns.

Lead the architecture and development of reliable AI-powered email applications across backend, mobile, and desktop platforms. Design APIs and workflow systems supporting orchestration, state, tool use, retries, fallbacks, and failure handling. Lead a small senior engineering team, make architectural trade-offs, mentor engineers, and establish strong production practices including observability, monitoring, testing, scalability, security, and operational excellence. Partner with ML leadership to deliver robust, high-quality product experiences.

Design, implement, and operate cloud-scale telemetry platforms and data pipelines for Azure Monitor. Lead cross-team architecture, mentor engineers, improve AI-enabled development practices, ensure security/compliance, and resolve complex production incidents.

The role involves leading initiatives for vector search in Elasticsearch, enhancing features, resolving bugs, and contributing to community engagements in a distributed team setting. A strong background in vector similarity and Java is crucial.

Lead technical direction and hands-on execution for major software products and systems. Design scalable architectures across backend, frontend, APIs, databases, and infrastructure; write code; drive architecture decisions; solve production issues; improve testing, security, observability, and development practices; lead critical initiatives; and mentor engineers across distributed international teams.

Lead and execute cross-team initiatives to improve developer experience: build production AI integrations and developer tools, define build/release standards, eliminate CI/source-control bottlenecks, and drive technical strategy and operational excellence across Riot.

Lead design and prototyping of generative AI experiences for autonomy development; drive UX for Hivemind products; perform user research, collaborate with CTO and product leads, and deliver reference implementations and integrations across full-stack web and edge systems.

The Principal Software Engineer will embed with product teams to solve complex technical problems, deliver production code, and make application and service-level architectural decisions. The role owns shared services, reliability, performance, incident response, and cross-system issue diagnosis. It also leads solution design, mentors engineers through influence, supports multiple products and domains, and establishes effective standards for AI-assisted software development.

Lead design and implementation of core platform infrastructure for an Agentic AI platform. Build high-performance Rust systems, support production deployments, collaborate with ML engineers, design scalable data architectures, troubleshoot performance and scalability issues, and cultivate a collaborative, inclusive engineering culture.

Lead technical strategy and architecture for data-centric solutions across programs. Oversee data acquisition, harmonization, processing, storage, analysis, dissemination, and product lifecycle. Serve as technical lead/Product Owner, define enterprise data standards, decompose backlogs, prioritize features, advise leadership on analytics opportunities, and ensure mission-focused delivery within high-clearance environments.

Lead design and reliability of a financial data extraction platform, minimizing human validation through AI, and enhance system correctness for scale.

Drive architecture, design, and implementation of large-scale software systems. Lead technical strategy, mentor engineers, collaborate cross-functionally, ensure code quality and operational reliability, and guide delivery of complex features and platform improvements.

As a Principal Software Engineer, you will lead the architecture of AI platforms at SpaceX, focusing on scalable solutions and risk-mitigation tools, while mentoring engineers and driving cultural change.

Lead development, integration, and delivery of modular modeling and simulation software. Provide architecture and technical leadership, ensure verification/validation and model fidelity, optimize performance and CI/CD pipelines, integrate simulation components with system interfaces, and coordinate with systems, hardware, and test teams. On-site role requiring active Top Secret clearance and ability to obtain SAP/PAR.

Lead architecture and roadmap for Azure PostgreSQL systems; design and review scalable, maintainable database engine features (query processing, storage, transaction logging, recovery, versioning, IO, scale-out). Influence coding standards and run code reviews, write proof-of-concept or production code, contribute to open-source PostgreSQL/Linux, and participate in rotational on-call operations.

Own the architecture and delivery of mission-critical backend projects for a secure crypto wallet infrastructure platform. Define database, microservice, and integration architecture; resolve performance and reliability issues; improve CI/CD, observability, and engineering processes; shape technical strategy; mentor engineers; and support client discussions. The role requires deep backend, cloud, database, security, and applied cryptography expertise, with leadership experience in fintech or blockchain.

Lead design and delivery of scalable, secure full-stack systems; mentor engineers; integrate AI-driven and agent-based workflows; ensure cloud-native, containerized deployments and secure SDLC practices.

The Principal Software Engineer leads the design and development of scalable software solutions, mentors engineers, and drives architectural decisions while collaborating with cross-functional teams.

Design and develop web applications, mentor teammates, shape architectural decisions, write clean code, conduct testing, and troubleshoot issues.

The Principal Software Engineer will lead the development of Node-based applications, ensuring alignment with business goals and mentoring engineers. Responsibilities include designing scalable systems, managing product requirements, and utilizing AI tools for software development.

As a Principal Software Engineer, you'll develop tools for continuous integration in Starship software, enhancing collaboration and efficiency for engineers.

The Principal Software Engineer will analyze, design, and implement software solutions, debugging and enhancing products for various applications while ensuring documentation and user requirements are met.