About Zscaler

Zscaler accelerates digital transformation so our customers can be more agile, efficient, resilient, and secure. Our cloud native Zero Trust Exchange platform protects thousands of 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 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 make a positive difference on a global scale, we invite you to bring your talents to Zscaler and help shape the future of cybersecurity.

Our Engineering team built the world's largest cloud security platform from the ground up, and we keep building. With more than 100 patents and big plans for enhancing services and increasing our global footprint, the team has made us and our multitenant architecture today's cloud security leader, with more than 15 million users in 185 countries. Bring your vision and passion to our team of cloud architects, software engineers, security experts, and more who are enabling organizations worldwide to harness speed and agility with a cloud-first strategy.

We are looking for a Principal Software Development Engineer to our Zero Trust Exchange team. Reporting to the Sr Manager of Software Engineering, you'll be responsible for:

Conducting comprehensive performance investigations across production and pre-production environments, network stack, microservices, and client-side browser performance
Advocating for and implement "shift-left" performance strategies, focusing on systemic fixes and architectural improvements to prevent performance regressions and minimise reactive "firefighting"
Analysing and optimising front-end application performance using advanced browser tools, focusing on critical metrics such as Time to First Byte (TTFB), Largest Contentful Paint (LCP), and Total Blocking Time (TBT)
Developing and maintaining specialised performance tooling, tracing scripts (e.g., EBPF), and advanced visualisations like Flame Graphs to identify and communicate complex bottlenecks
Collaborating closely with development and infrastructure teams, providing expert guidance on performance design, code optimisation, and efficient utilisation of operating system and network resources

What We're Looking for (Minimum Qualifications)

8+ years of experience specialising in systems performance engineering, with a foundational understanding of operating system internals (Linux) and core resource management (CPU, Memory, Disk, Network)
Hands-on experience with advanced Linux performance tools, including perf, DTrace, or eBPF/BPF Performance Tools, capable of conducting in-depth kernel-level analysis
In-depth knowledge of k8s performance considerations, including cluster capacity planning, CNI overhead, resource limits (requests and limits), and efficient pod scheduling
Expertise in utilising advanced profiling features in Chrome Developer Tools (Lighthouse, Performance tab) to diagnose rendering jank, JavaScript execution time, and core web vitals

What Will Make You Stand Out (Preferred Qualifications)

Experience tuning cloud provider infrastructure and services (e.g., AWS EC2/EKS, GCP GKE) for optimal price-performance ratios
Familiarity with the concepts and principles of proactive performance management and capacity planning
Experience generating and interpreting advanced performance visualisations such as Flame Graphs and Heat Maps

#LI-HYBRID

#LI-GL2

At Zscaler, we are committed to building a team that reflects the communities we serve and the customers we work with. We foster an inclusive environment that values all backgrounds and perspectives, emphasizing collaboration and belonging. Join us in our mission to make doing business seamless and secure.

Our Benefits program is one of the most important ways we support our employees. Zscaler proudly offers comprehensive and inclusive benefits to meet the diverse needs of our employees and their families throughout their life stages, including:

Various health plans
Time off plans for vacation and sick time
Parental leave options
Retirement options
Education reimbursement
In-office perks, and more!

Learn more about Zscaler’s Future of Work strategy, hybrid working model, and benefits here.

By applying for this role, you adhere to applicable laws, regulations, and Zscaler policies, including those related to security and privacy standards and guidelines.

Zscaler is committed to providing equal employment opportunities to all individuals. We strive to create a workplace where employees are treated with respect and have the chance to succeed. All qualified applicants will be considered for employment without regard to race, color, religion, sex (including pregnancy or related medical conditions), age, national origin, sexual orientation, gender identity or expression, genetic information, disability status, protected veteran status, or any other characteristic protected by federal, state, or local laws. See more information by clicking on the Know Your Rights: Workplace Discrimination is Illegal link.

Pay Transparency

Zscaler complies with all applicable federal, state, and local pay transparency rules.

Zscaler is committed to providing reasonable support (called accommodations or adjustments) in our recruiting processes for candidates who are differently abled, have long term conditions, mental health conditions or sincerely held religious beliefs, or who are neurodivergent or require pregnancy-related support.

Sr. Staff Software Development Engineer

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