Principal Software Development Engineer - Rust, LLM, Networking

Zscaler•San Jose, CA

8h•Hybrid

About The Position

Zscaler accelerates digital transformation to ensure our customers can be more agile, efficient, resilient, and secure. As an AI-forward enterprise, we are constantly pushing the envelope, leveraging the world’s largest security data lake to power our cloud-native Zero Trust Exchange platform. This innovation protects our customers from cyberattacks and data loss by securely connecting users, devices, and applications in any location. Here, impact in your role matters more than title and trust is built on results. We say, impact over activity. We seek innovators who actively use AI to amplify their impact and who thrive in an environment where we leverage intelligent systems to stay ahead of evolving threats. We believe in transparency and value constructive, honest debate—we’re focused on getting to the best ideas, faster. We build high-performing teams that can make an impact quickly and with high quality. To do this, we are building a culture of execution centered on customer obsession, collaboration, ownership, and accountability. We value high-impact, high-accountability with a sense of urgency where you’re enabled to do your best work and embrace your potential. If you’re driven by purpose, thrive on solving complex challenges, and want to be part of the team that’s helping to secure the AI age, we invite you to bring your talents to Zscaler and help shape the future of cybersecurity. We are hiring a Principal Software Development Engineer to be a founding member of our AI Security Team, offering the chance to build a high-reliability, low-latency AI security solution designed to scale for hundreds of millions of users. In this role, reporting to the Director, Software Development Engineering, you will be responsible for designing and implementing core infrastructure components and distributed systems while collaborating closely with various stakeholders throughout the development lifecycle. This is a hybrid role, reporting in to the San Jose, CA office 3 days a week.

Requirements

12+ years of software engineering experience
Deep experience in systems programming using Rust, with a focus on asynchronous frameworks such as Tokio or async-std.
Proven ability to design and implement horizontally scalable, highly available, and observable distributed systems.
Strong command of Linux internals, including kernel-user space interaction, networking, sockets, and namespaces.
Skilled in performance instrumentation, containerized environments, Git workflows, and CI/CD pipelines.

Nice To Haves

Expert in systems languages such as C/C++ or Rust, with a focus on performance optimization.
Deep understanding of Linux networking stacks, Kubernetes networking, service meshes, and LLM model optimization.
Practical experience with gRPC, Protobufs, and L4-L7 networking protocols, including TCP/IP, TLS, QUIC, HTTP, and WebSockets (WSS).
Direct experience in validating AI-driven products, including understanding of model performance metrics and MLOps principles.

Responsibilities

Architect, develop, and optimize a low-latency, high-throughput AI Security plane utilizing Rust, specifically leveraging its async/await model for highly efficient I/O and service-oriented architecture.
Build resilient, distributed, and scalable systems, emphasizing concurrency, fault tolerance, and robust messaging protocols.
Implement and maintain gRPC services and APIs to ensure seamless integration of the AI Security plane with control and orchestration infrastructure.
Systematically enhance performance across the entire stack, including LLM models, by employing profiling tools for both kernel-space and user-space components.
Contribute actively to the team through technical documentation, system design reviews, code reviews, and by mentoring junior engineering staff.
Lead complex, multi-functional projects and initiatives, defining the technical roadmap and driving execution across teams.