Principal Engineer

About Us

At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. Cloudflare was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company. 

At Cloudflare, we’re not looking for people who wait for a polished roadmap; we’re looking for the builders who see the cracks in the Internet that everyone else has simply learned to live with. We value candidates who have the instinct to spot a "normalized" problem and the AI-native curiosity to create a solution using the latest tools. Our culture is built on iteration, leveraging AI to ship faster today to make it better tomorrow, while ensuring that every improvement, no matter how small, is shared across the team to lift everyone up. If you’re the type of person who values curiosity over bureaucracy, and that AI is a partner in solving tough problems to keep the Internet moving forward, you’ll fit right in.

Available Locations: Austin, TX

About the role

Cloudforce One is Cloudflare's threat operations and research team, responsible for identifying and disrupting cyber threats ranging from sophisticated cyber criminal activity to nation-state sponsored advanced persistent threats (APTs). Cloudforce One works in close partnership with external organizations and internal Cloudflare teams, continuously developing operational tradecraft and expanding ever-growing sources of threat intelligence to enable expedited threat hunting and remediation. Members of Cloudforce One are at the helm of leveraging an incredibly vast and varied set of data points that only one of the world's largest global networks can provide. The team is able to analyze these unique data points, at massive scale and efficiency, synthesizing findings into actionable threat intelligence to better protect our customers.

Cloudflare's Trust & Safety team is the frontline defense against platform abuse — phishing, malware distribution, fraud, and content that undermines the safety of the internet. Together, these teams form a unified capability: from tracking an adversary's infrastructure to dismantling it at network scale.

What you'll do

Cloudflare is a system spanning the globe, on a mission to make the internet better, safer, and more powerful every day. We are looking for a Principal Engineer who is equal parts architect, threat analyst, and disruptor — someone who doesn't just build systems but fundamentally rethinks how we detect, analyze, and neutralize threats across one of the world's largest networks.

This is not a role that lives in a single team or a single codebase. You will operate across the full breadth of Cloudflare Products, diving into whatever problem is most critical — whether that's redesigning a detection pipeline in Kubernetes, deploying a new mitigation capability at the edge via Workers, building agentic AI workflows that automate analyst tradecraft, or architecting a data system that processes trillions of signals per day. You will be the person teams turn to when the problem is ambiguous, the architecture is complex, and the adversary is sophisticated.

Our ideal candidate has deep technical expertise in distributed systems architecture and an equally deep understanding of how threat actors operate — their tactics, techniques, procedures, and infrastructure. You think like an attacker and build like an engineer who has been burned by production incidents at 3 AM. You are energized by hard problems, impatient with the status quo, and have a track record of shipping solutions that others said couldn't be done.

This role may require flexibility to be on-call outside of standard working hours to address technical issues as needed.

Responsibilities

• Drive architectural direction and technical strategy across Cloudforce One engineering, spanning services that run in Kubernetes, on the edge (Workers, D1), and across Cloudflare's global network.
• Identify and dismantle technical bottlenecks, legacy patterns, and architectural debt that slow down threat detection and abuse response — then replace them with systems that are faster, more reliable, and more elegant.
• Design and build critical data pipelines and services to collect, enrich, analyze, and expose threat intelligence and abuse signals at massive scale, helping identify Tactics, Techniques, and Procedures (TTPs) and Indicators of Compromise (IOCs).
• Serve as a technical force multiplier across multiple concurrent projects — you will context-switch between threat intelligence platforms, abuse detection systems, legal response tooling, and customer-facing security products as priorities demand.
• Bring a threat-informed perspective to engineering decisions: understand how adversaries adapt, how detection rules degrade, and how to build systems that stay ahead of evolving attack techniques.
• Collaborate with Threat Intelligence researchers, Trust & Safety analysts, Product, Legal, and other engineering teams to translate complex security and compliance requirements into scalable, production-grade solutions.
• Mentor and elevate the engineering talent around you — set the bar for code quality, system design, operational rigor, and security-first thinking across both organizations.
• Develop and champion agentic AI workflows and AI-assisted development practices that accelerate threat hunting, detection engineering, and abuse investigation.
• Own the operational excellence of the systems you touch, including participation in on-call rotations and incident response.

Desirable Skills, Knowledge, and Experience:

• 15+ years of cyber security experience with an emphasis on building systems to present adversarial trends and techniques both as an internal reputational service and a product facing analyst service.
• 10+ years of experience building and operating large-scale distributed systems in production, with demonstrated expertise in complex system architecture and design.
• Deep, hands-on proficiency in Go and/or TypeScript, with production experience deploying services in Kubernetes and on edge computing platforms (e.g., Cloudflare Workers, D1/SQLite-at-the-edge).
• Subject matter expertise in threat intelligence, adversarial analysis, or detection engineering — you understand the Cyber Kill Chain, know how to track TTPs, and can reason about attacker infrastructure at scale.
• Proven ability to work across organizational boundaries and lead technical initiatives that span multiple teams, codebases, and problem domains simultaneously.
• Experience with AI-assisted development and agentic AI workflows.
• Strong architectural judgment — you know when to build, when to refactor, and when to burn it down and start over.
• Experience designing and operating critical data pipelines (Kafka, Temporal, or similar) and working with SQL databases (PostgreSQL) and caching layers (Redis) at scale.
• Excellent communication skills — you can explain a complex system design to a VP and debug a race condition with a junior engineer in the same afternoon.
• A track record as a disruptor: you have examples of fundamentally improving how a team, system, or organization operates, not just shipping features.

Bonus Points:

• Experience in the Trust & Safety or platform abuse domain — phishing detection, malware analysis, fraud prevention, or content moderation at scale.
• Proficiency in writing detection rules using YARA, Snort, or similar detection languages.
• Experience analyzing adversary TTPs across web-based threat vectors, including phishing obfuscation techniques (HTML encoding, JavaScript redirects, Base64, embedded scripts).
• Familiarity with Rust.
• Experience with Terraform and infrastructure-as-code practices.
• Prior experience building threat intelligence platforms, IOC distribution systems, or automated mitigation pipelines.
• Experience with React for internal tooling and analyst-facing applications.
• Deep understanding of DNS, TLS/SSL, HTTP, and web security standards.

Equity

This role is eligible to participate in Cloudflare’s equity plan.

Benefits

Cloudflare offers a complete package of benefits and programs to support you and your family, including medical, dental, and vision insurance, a 401(k) plan with company match, flexible paid time off, and fertility & family-forming benefits.

What Makes Cloudflare Special?

We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.

Project Galileo: Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers--at no cost.

Athenian Project: In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we've provided services to more than 425 local government election websites in 33 states.

1.1.1.1: We released 1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy-centric public DNS resolver. This is available publicly for everyone to use - it is the first consumer-focused service Cloudflare has ever released. Here’s the deal - we don’t store client IP addresses never, ever. We will continue to abide by our privacy commitment and ensure that no user data is sold to advertisers or used to target consumers.

Sound like something you’d like to be a part of? We’d love to hear from you!

Please note that applicants who progress to the offer stage of the interview process may be asked to attend an in-person interview within one of the Cloudflare Offices or Cloudflare Hubs.  More details about this will be available at that stage of the interview process.

This position may require access to information protected under U.S. export control laws, including the U.S. Export Administration Regulations. Please note that any offer of employment may be conditioned on your authorization to receive software or technology controlled under these U.S. export laws without sponsorship for an export license.

Cloudflare is proud to be an equal opportunity employer.  We are committed to providing equal employment opportunity for all people and place great value in both diversity and inclusiveness.  All qualified applicants will be considered for employment without regard to their, or any other person's, perceived or actual race, color, religion, sex, gender, gender identity, gender expression, sexual orientation, national origin, ancestry, citizenship, age, physical or mental disability, medical condition, family care status, or any other basis protected by law. We are an AA/Veterans/Disabled Employer.

Cloudflare provides reasonable accommodations to qualified individuals with disabilities.  Please tell us if you require a reasonable accommodation to apply for a job. Examples of reasonable accommodations include, but are not limited to, changing the application process, providing documents in an alternate format, using a sign language interpreter, or using specialized equipment.  If you require a reasonable accommodation to apply for a job, please contact us via e-mail at hr@cloudflare.com or via mail at 101 Townsend St. San Francisco, CA 94107.