Top Principal Software Engineer Jobs in San Francisco, CA

Designs scalable software architectures, leads technical projects, develops complex backend and frontend features, and owns solutions through the full lifecycle. Provides engineering mentorship, reviews code and designs, researches technologies, establishes quality standards, troubleshoots distributed systems, and collaborates across product and program teams. The role requires significant software development and engineering leadership experience, with emphasis on backend development, TypeScript, AWS, distributed systems, and regulated software environments.

Leads architecture and hands-on development for AI frameworks, performance systems, benchmarking, and developer tools. Investigates issues across models, compilers, runtimes, services, and accelerator hardware; improves model onboarding, runtime performance, reliability, hardware utilization, and Azure efficiency. Establishes scalable measurement and observability capabilities, influences cross-team technical strategy, delivers production solutions, and mentors engineers while advancing engineering quality and maintainability.

Lead architecture and hands-on development of Microsoft's AI Safety Platform, building observability, detection, investigation, threat-hunting, and distributed data-processing capabilities. Design attack detection infrastructure, correlate high-volume telemetry, apply AI security research, conduct security and privacy reviews, and partner across engineering, science, and incident response teams. Mentor engineers and provide technical leadership for complex AI security systems.

Principal Software Engineer responsible for setting engineering standards across Shippo’s data organization. Designs and builds interfaces between application services, ML systems, and data platforms; develops scalable, secure, observable production systems; guides technical architecture through RFCs and design reviews; productionizes analytical and prototype work; advises on ML workflows and agentic AI; and mentors engineers while driving cross-team technical direction.

Define architectural direction for Azure Specialized platform services and lead the design of highly available distributed cloud systems. Drive reliability, scalability, observability, security, diagnostics, and operational improvements across engineering organizations. Establish service health frameworks, SLOs, metrics, and governance for mission-critical services. Mentor engineers, influence technical strategy, resolve complex cross-system challenges, and advance AI-assisted troubleshooting and platform modernization.

Lead the technical direction and implementation of large-scale SaaS product features. Build secure, reliable, maintainable, well-tested software; evaluate architectural trade-offs; debug team inefficiencies; and contribute to code reviews, documentation, and complex bug fixes. Collaborate across product, design, and engineering, influence strategy, identify organizational blockers, mentor engineers, and improve engineering practices around testing, performance, security, privacy, and reliability.

Lead the design and evolution of cloud-native platforms, distributed systems, and infrastructure services at large scale. Define architecture across compute, networking, storage, datacenter, and AI infrastructure environments. Improve automation, lifecycle management, observability, reliability, security, and developer productivity. Guide technical strategy across engineering organizations while contributing to GPU, HPC, bare-metal, networking, and distributed computing platforms. Mentor engineers and foster technical excellence through architecture reviews and cross-organizational collaboration.

Build, maintain, monitor, and scale enterprise platform services spanning IAM, communications, payments, and API gateways. Design highly available and fault-tolerant products, evaluate technical tradeoffs, contribute to platform roadmaps and technical strategy, and collaborate with product, architecture, and design teams. The role also mentors engineers, promotes software quality and operational excellence, and applies backend platform engineering, API, messaging, DevOps, and AI-assisted development expertise.

Lead design, build, deployment, and operation of highly resilient, high-throughput configuration and publishing systems. Define long-term architecture and strategy, mentor senior engineers, diagnose and fix performance bottlenecks, and leverage AI tools to improve engineering productivity and platform capabilities.

Lead hardware strategy, performance architecture, and benchmarking for large-scale Microsoft 365 and AI workloads. Investigate performance, scalability, and efficiency across compute, GPU, memory, storage, networking, and accelerators. Partner with Azure and platform teams, build AI-assisted performance engineering tools, and influence cross-organizational architecture and infrastructure decisions.

Lead the architecture and technical direction of large-scale Azure cloud infrastructure and machine learning platforms. Design distributed systems for model training, inference, data processing, and platform services; improve compute efficiency, reliability, security, scalability, and observability; guide Kubernetes and AI workloads in production; support MLOps practices; establish engineering standards; and mentor engineers across teams.

Principal frontend-focused software engineer responsible for leading frontend architecture, standards, tooling, accessibility, performance, testing, and deployment practices. The role delivers scalable customer-facing web applications, component libraries, and design systems using React or Angular. It includes cross-functional product collaboration, technical decision-making, mentoring, modernization initiatives, and occasional full-stack work. The position is remote, requires U.S. citizenship, Public Trust 6C eligibility, and approximately 0–10% business travel.

Design and develop software to onboard hardware accelerators and optimize storage datapaths for Azure Storage. Drive design, debugging, performance tuning, operations, and cross-team collaboration across research, compute, and storage to improve throughput, scale, reliability, and observability.

Lead design and build of production-ready cloud and AI systems, prioritize security and reliability, ship solutions quickly using modern engineering practices, collaborate with cross-functional teams, mentor engineers, drive customer adoption, and deliver reusable assets and end-to-end complex deliveries.

Design and implement PostgreSQL internals, indexing, query engine extensions, and storage-layer features to support large-scale document workloads on Azure. Profile distributed systems, tune performance, collaborate with open-source communities, conduct design/code reviews, and drive cross-team alignment for mission-critical database features.

Develop and optimize GPU kernels, compilers, runtimes, and distributed inference systems for large language model serving. Improve latency, throughput, reliability, and hardware efficiency through profiling and low-level performance optimization. Integrate scalable improvements into production systems, collaborate across model, infrastructure, compiler, and hardware teams, and mentor engineers. Principal-level contributors additionally lead cross-stack initiatives and create reusable performance capabilities across models and hardware generations.

Leads the technical vision, architecture, and execution of AI performance, framework, benchmarking, and developer-productivity initiatives. Drives cross-team architecture, resolves complex systems trade-offs, mentors technical leaders, and contributes hands-on through prototyping, implementation, reviews, debugging, observability, and automation. Delivers measurable improvements in model onboarding speed, runtime performance, reliability, hardware utilization, and Azure capacity efficiency across models, frameworks, compilers, runtimes, systems, services, and hardware.

Leads the strategic direction of backend and full-stack engineering, architects scalable distributed systems and microservices, and drives modernization, reliability, security, and performance initiatives. Designs APIs, data architectures, pipelines, infrastructure, and observability practices; delivers customer-facing service improvements; establishes engineering standards; and mentors engineers. Collaborates across product and technical teams to make architecture and business trade-offs and lead large-scale initiatives from vision through production.

Design and implement high-performance backend systems in Rust, optimize architectures, participate across the development lifecycle (debugging, testing, optimization), integrate third-party devices and data, incorporate AI tools, mentor senior engineers, and lead architectural and technical strategy across teams.

Design and build scalable AI-first experimentation and growth systems: telemetry, experiment assignment, feature flighting, rollout automation, and risk controls. Lead cross-team initiatives, partner with Product/Data Science/Design, write production code, review implementations, and raise engineering and experimentation quality across products.

Set technical direction org-wide, own highest-stakes architectural bets, lead the AI/agents rebuild, raise engineering standards, mentor senior engineers, and align teams with product and platform strategy.

Build and operate production agentic AI systems for Salesforce Database engineering and operations. Responsibilities include knowledge graphs and agentic memory, LLM orchestration, tool and MCP integration, evaluation infrastructure, tracing, guardrails, telemetry, workflow automation, root-cause analysis, anomaly detection, and self-remediation. The role requires hands-on full-stack delivery, distributed-systems expertise, Python and Java programming, and collaboration across database engineering teams.

Provides hands-on technical leadership for Pantheon’s P1 zero-to-one product and company-wide engineering strategy. Owns architecture across real-time collaboration, APIs, data, publishing, integrations, and developer experience; establishes reliability, security, observability, and delivery standards; guides build-versus-buy decisions; mentors senior engineers; partners with product, design, security, infrastructure, and customers; and contributes code to validate architecture and unblock critical initiatives.

Lead architecture and engineering for Microsoft’s enterprise Insider Risk platform. Build scalable, secure, privacy-conscious systems supporting risk modeling, behavioral analytics, detections, monitoring, investigations, workflows, and case orchestration. Partner with security, legal, HR, privacy, data science, and business teams to address complex risk scenarios. Drive technical strategy, align cross-team delivery, mentor engineers, and uphold reliability, confidentiality, compliance, and responsible data-use standards.

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.