Principal Software Development Engineer

Zscaler is a pioneer and global leader in zero trust security. The world’s largest businesses, critical infrastructure organizations, and government agencies rely on Zscaler to secure users, branches, applications, data & devices, and to accelerate digital transformation initiatives. Distributed across more than 160 data centers globally, the Zscaler Zero Trust Exchange platform combined with advanced AI combats billions of cyber threats and policy violations every day and unlocks productivity gains for modern enterprises by reducing costs and complexity.

Here,
impact in your role matters more than title and trust is built on results. 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 champion an “AI Forward, People First” philosophy to help us accelerate and innovate, empowering our people to embrace their potential. If you’re driven by purpose, thrive on solving complex challenges and want to make a positive difference on a global scale, we invite you to bring your talents to Zscaler to help shape the future of cybersecurity.

We are looking for a Principal Software Engineer to join our team in San Jose, reporting to the Sr Manager, Software Engineering, QA within the ZIA System Test and Automation team. In this role, you will architect, design, develop, and maintain a highly scalable system test automation infrastructure for a cloud product processing over 500 billion transactions per day. You will serve as an advocate for testing at scale, pushing the limits of our software while mentoring junior engineers and ensuring the delivery of robust cloud security solutions.

• Collaborate with cross‑functional teams to design, develop, and maintain cloud‑based software solutions while optimizing the regression cycle
• Architect, design, develop, and maintain a resilient system test automation infrastructure for a massive‑scale cloud product
• Build repeatable system‑level automation suites to validate L4-L7 technologies, utilizing your expertise in cloud firewalls and tunneling methods
• Take ownership of issue resolution by diagnosing complex customer challenges, recreating production issues, and providing actionable workarounds
• Mentor and guide more junior engineers, taking full ownership of feature testing and championing a culture of testing at scale

• You act like an owner. Your passion for the mission fuels your bias for action. You operate with integrity because you genuinely care about the outcome. You adapt to what’s needed, navigating seamlessly between high‑level strategy and hands‑on execution.
• You are a problem‑solver. You seek out challenges because you are energized by finding solutions, knowing that solving the hard problems delivers the biggest impact.
• You are customer‑obsessed. You build deep empathy for the customer—both internal and external—and anchor your decisions in solving their real‑world problems. You champion their needs from start to finish, knowing their success is our success.
• You think  connect your day‑to‑day work to the larger company mission and think globally. You build solutions, processes, and teams that are not just effective today but are built to last and support a high‑growth, global organization.
• You are resilient and adaptable. You view change as an opportunity and setbacks as temporary. You maintain composure and focus in high‑pressure situations, guiding yourself and your team through complexity with a steady, positive hand.

• 12+ years of overall software development experience with strong programming skills building scalable frameworks in Python
• Deep understanding of automated, functional, integration, and performance testing processes for cloud security products
• Proven ability to develop robust test automation frameworks and internal tools that cover various layers of the software…