Principal Software Development Engineer Rust LLM Networking

About Zscaler:
Zscaler accelerates digital transformation to ensure our customers can be more agile, efficient, resilient, and secure. As an AI-forward enterprise, we constantly push the envelope, leveraging the world’s largest security data lake to power our cloud-native Zero Trust Exchange platform. This innovation protects 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 where intelligent systems help 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 design and implement core infrastructure components and distributed systems while collaborating closely with various stakeholders throughout the development lifecycle.

This is a hybrid role, reporting to the San Jose, CA office 3 days a week.

• 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 mentoring junior engineering staff.
• Lead complex, multi-functional projects and initiatives, defining the technical roadmap and driving execution across teams.

Drive the mission with an owner's mindset, seamlessly bridging high-level strategy and detailed, hands-on execution. Actively seek challenges and find complex solutions that deliver maximum impact. Deeply empathize with internal and external stakeholders, anchoring every decision in addressing their real-world problems. Maintain strong technical curiosity, continually seeking more secure, scalable, and effective methods to accelerate transformation. Connect your work to the company's broader mission, designing solutions to support high-growth, global organizational needs.

• 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 name spaces
• Skilled in performance instrumentation, containerized environments, Git workflows, and CI/CD pipelines

• Expert in systems languages such as C/C++ or Rust, with a focus on performance optimization
• Deep understanding of Linux networking stacks, Kubernetes networking,…