Top Principal Software Engineer Jobs in Los Angeles, CA

Serve as the technical anchor for HubSpot’s Breeze Assistant platform. Architect and ship scalable distributed and agentic AI systems using LLMs, RAG, vector databases, and tool-calling. Build platform primitives, customer-context integrations, dynamic artifacts, and multi-step workflows across HubSpot and third-party tools. Drive reliability, evaluation, observability, guardrails, privacy, and production readiness while mentoring engineers and partnering cross-functionally on product and platform strategy.

Provides hands-on software development, technical leadership, architecture support, and mentorship across multiple mission-focused teams. Designs full-stack applications, distributed and event-driven systems, scalable APIs, enterprise integrations, and modern Angular interfaces. Collaborates on DevSecOps, CI/CD, observability, security, cloud-native deployment, and technical governance while resolving complex architectural and performance challenges for Space Force mission systems.

As a Senior Principal Software Engineer, you'll develop a unified data platform, architect infrastructure, implement APIs, and mentor teams, focusing on data processing and reliability.

Design and build Azure Kubernetes Service features and AI-native infrastructure, improve service reliability and developer velocity, automate incident prevention/remediation, integrate AI tools, and operate distributed, containerized systems at cloud scale.

Lead technical strategy and architecture for Azure Storage geo-replication, data protection, failover orchestration, and business continuity. Drive cross-team delivery, operational excellence, telemetry, automation, AI-assisted operations, and represent the team in executive and customer engagements.

Design and deliver large-scale, resilient AI and Kubernetes infrastructure for hybrid environments. Implement, optimize, and maintain cloud-native, container orchestration solutions; integrate AI capabilities; participate in on-call rotations; mentor engineers and drive reliability, observability, and performance at scale.

Design and develop electromagnetic warfare and spectrum operations software, including data models, RF propagation integrations, C2 and sensor APIs, AI-assisted coding workflows, and deployments across cloud, on-premises, and edge environments. Demonstrate software to customers, translate feedback into requirements, document and test solutions, mentor developers, and support agile delivery. The role requires an active US Top Secret/SCI clearance and travel to customer sites.

Lead design and implementation of scalable, low-latency ad experience systems. Mentor engineers, review code/tests, build observability, support on-call rotations, prototype ad formats, and translate product requirements into production-ready microservices.

Lead architecture and development of manufacturing systems and integrations (MES, ERP, QMS, WMS). Build production factory software, define APIs/data models, establish engineering standards, ensure auditability/observability, and partner with cross-functional operations teams. Mentor engineers and operate hands-on as the first senior technical leader in a fast, regulated manufacturing environment.

Lead rendering engineer building engine and rendering systems for a new AAA MMO. Collaborate with art and design to implement, optimize, and tool rendering pipelines, improve performance, and resolve asset/pipeline issues across platforms.

Architect and develop foundational edge-computing runtime and integration platforms for connected-home devices. Build software models for device, spatial, and occupancy data; prototype and productionize new concepts; evaluate architectures; and provide technical leadership through design reviews, coding standards, mentoring, and cross-functional collaboration. The role spans edge computing, IoT, distributed systems, embedded environments, intelligent agents, networking, and secure systems within an exploratory R&D organization.

Design and deliver distributed storage systems for AI and machine learning workloads at hyperscale. Lead architecture, development, testing, deployment, and innovations in scalability, performance, security, and efficiency. Collaborate with AI researchers and cloud infrastructure engineers, mentor engineers, and guide technical strategy for high-availability, durable, high-performance storage supporting training and inference.

Design and operate large-scale, AI-native cloud infrastructure (especially Kubernetes/AKS). Improve service quality, automate incident prevention/remediation, accelerate engineering productivity, and integrate AI tools into development workflows.

Lead the architecture and modernization of a complex enterprise SaaS platform while remaining hands-on with critical software design and development. Define technical direction, improve scalability, reliability, security, performance, and maintainability, and guide design and code reviews. Partner across engineering and product teams, resolve complex technical challenges, establish engineering standards, mentor engineers, and translate architectural strategy into practical delivery.

Lead the technical vision, roadmap, and development of Elasticsearch’s ES|QL analytical engine and query capabilities. Design data-intensive systems, algorithms, APIs, and compute infrastructure; research search and analytics technologies; collaborate across product and engineering teams; mentor senior engineers; and contribute hands-on modern Java development. The role requires autonomous technical leadership, expertise in database internals and analytics systems, and the ability to guide complex projects from conception through delivery.

Lead architecture and technical direction for an AI-first SaaS product (Growth Studio). Define scalable services, APIs, data flows, and AI-enabled workflows; guide integrations, run architecture/code reviews and POCs; mentor engineers; produce technical documentation; and partner with product, UX, QA, and ops to deliver reliable, secure, and maintainable platform capabilities for GovCon customers.

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.

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.

Develop, test, debug, and integrate software for advanced navigation systems supporting national defense products. Apply full SDLC practices, software design, coding, system integration, Model-Based Engineering, and Agile development. Collaborate across multidisciplinary teams, solve complex problems, communicate effectively, and provide technical leadership. The role is full-time onsite in Woodland Hills, California, requires U.S. citizenship, and requires the ability to obtain and maintain a Secret clearance.

Develop and test software for advanced navigation systems, including software and system integration on hardware. Apply model-based engineering and Agile practices, debug code, translate requirements into designs, and support mission- and safety-critical systems. Collaborate across multidisciplinary teams while providing technical leadership, problem-solving, and customer communication. The role requires MATLAB or Simulink, C/C++/Python, workflow tools, U.S. citizenship, onsite work, and the ability to obtain and maintain a Secret clearance.

Set technical direction for Elastic Cloud Serverless control-plane initiatives, designing distributed systems that orchestrate projects across AWS, Google Cloud, and Azure. Lead multi-quarter, cross-team delivery; write and review Go code; improve reliability, security, and cost efficiency; investigate incidents; participate in on-call; mentor engineers; and advise product and engineering leaders on technical trade-offs and roadmap decisions.

Leads architecture, design, development, integration, validation, and deployment of an in-flight connectivity software platform. Oversees technical execution across aircraft networks, satellite and air-to-ground connectivity, cabin systems, hardware, and ground interfaces. Establishes development and testing standards, resolves technical and process issues, collaborates with global engineering and product teams, supports customers and sales, and mentors or manages technical personnel.

Owns technical direction and execution for major products and systems. Designs scalable backend, frontend, API, database, and infrastructure solutions; writes production code; drives architecture decisions; resolves complex engineering problems; improves testing, security, observability, and development practices; and mentors engineers across teams. The role requires leading major initiatives from design through production in a globally distributed environment.

Lead architecture, design, and delivery of flight and ground software for a major satellite constellation. Develop embedded RTOS applications and hardware drivers, integrate and validate software with hardware (ICDs, DIO/AIO), support on-orbit operations, mentor teams, and ensure reliability, security, and mission success for defense and aerospace programs.

Lead chief software engineer for a major constellation program: define end-to-end flight and ground software architecture, develop embedded flight software and hardware drivers, integrate and test with CI and hardware-in-the-loop, mentor teams, support on-orbit operations, and ensure mission-critical reliability and security. Requires active TS/SCI and extensive aerospace/defense experience.