Skip to content

Principal Data Scientist

Cloudflare
staff
Location

United Kingdom

Work Type

Onsite

Seniority

staff

Posted

September 9, 2026


Total Compensation
€190,666
Yearly Savings (Comfortable)
€169,694
Want to apply for this job?

Subscribe to access the application link and 15,000+ more jobs

Job Description

Who you are

  • Fraud and bots at scale. You have experience across fraud, abuse, and/or bot detection on large, high-velocity traffic. You may focus on one, but you transfer instincts between them
  • Strong fundamentals, fluent in data. You have solid applied statistics, machine learning, and AI methodology fundamentals. You choose the right technique for the problem, and are fluent with large-scale data
  • You have at least 8-10 years of experience professionally working in Data Science, ML Engineering, or Software Engineering
  • Demonstrated ability to make ambiguous, high-stakes technical decisions with incomplete information
  • You are very comfortable with Python & SQL in production environments
  • At home in ground truth ambiguity. Building detections when ground truth is scarce is the heart of this job. You make real progress with weak, delayed, or absent labels and you're energized by adversaries that fight back
  • You don't burn signals. You understand (or are curious to learn) how to act on detections without tipping your hand, knowing that how you deploy and respond can erode your future visibility
  • Pragmatic about complexity. You know when a simple solution beats a complex one, and you don't chase small gains at disproportionate cost
  • Disciplined in code. You apply strong programming and engineering best practices in both research and production code
  • Impact-driven and clear. You connect your work to business impact and communicate clearly across technical and non-technical stakeholders

What the job involves

  • Cloudflare’s Engineering Team is home to some of the industry’s top engineers, dedicated to building and scaling innovative software that handles a huge proportion of the Internet. Our Detection department sits at the heart of that mission: we identify automated, fraudulent, and malicious activity across the Internet and through our gateway
  • We develop advanced detection systems and machine learning models that operate at scale, collaborating with Product and Engineering teams across the company to protect our customers and stay ahead of the constantly evolving threat landscape
  • Lead the research, design, and evaluate detection models that identify automated, fraudulent, and malicious activity across Internet-scale data
  • Mentor others in how to uncover patterns and behaviors that distinguish adversaries from legitimate users
  • Own the detection measurement framework, defining metrics and evaluation strategies for problems where ground truth is noisy, delayed, or contested
  • Drive adoption of promising AI/ML techniques and represent Cloudflare in the broader research community
  • Drive cross-functional partnerships with ML Engineers, Data Engineers, and Product; Influence roadmaps and align detection strategy with company priorities
  • Shape long-term detection strategy, identifying gaps and opportunities that span multiple product areas

Benefits

  • Competitive pay: We offer a competitive total rewards package, where every employee is an owner of our stock.
  • Take-what-you-need vacation: We encourage employees to find a comfortable work-life balance by taking as many days off as they need while still being able to perform their jobs satisfactorily. (We really mean it!)
  • Paid maternity & paternity leave: Our global parental leave policy allows up to sixteen paid weeks of bonding leave time for all qualifying new parents.
  • Employee benefits: We offer a comprehensive benefits package including healthcare, life insurance, short- and long-term disability, pension plans in accordance with the market practice in our locations.
  • Commuter program: We are flexible about where we work and value connecting at the office. Our commuter benefits program is in place to support team members' commute to work via public transportation without the extra cost burden.
  • Wellbeing: Global offerings that provide mental health, childcare and family forming support to our employees across our offices.
More Jobs You Might Like
NLP Performance Engineer

G-Research

London

Helpful Resources
Salary & Savings Calculator

Compare salaries across European cities and calculate your potential savings. Understand cost of living and take-home pay for tech jobs in Europe.

Career Guides

Expert advice on landing high-paying tech jobs in Europe. Tips on interviews, salary negotiation, and career growth from The European Engineer.

Access 15,000+ High-Paying Tech Jobs

Get unlimited access to our full database of 15,000+ jobs with advanced filters, salary comparisons, and exclusive career guides from The European Engineer.