Principal Engineer - Cloudforce One

Available Locations: Austin, TX (US), London (UK)

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.  Our benefits programs can help you pay health care expenses, support caregiving, build capital for the future and make life a little easier and fun!  The below is a description of our benefits for employees in the United States, and benefits may vary for employees based outside the U.S.

Health & Welfare Benefits

• Medical/Rx Insurance
• Dental Insurance
• Vision Insurance
• Flexible Spending Accounts
• Commuter Spending Accounts
• Fertility & Family Forming Benefits
• On-demand mental health support and Employee Assistance Program
• Global Travel Medical Insurance

Financial Benefits

• Short and Long Term Disability Insurance
• Life & Accident Insurance
• 401(k) Retirement Savings Plan
• Employee Stock Participation Plan

Time Off

• Flexible paid time off covering vacation and sick leave
• Leave programs, including parental, pregnancy health, medical, and bereavement leave