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. 

We realize people do not fit into neat boxes. We are looking for curious and empathetic individuals who are committed to developing themselves and learning new skills, and we are ready to help you do that. We cannot complete our mission without building a diverse and inclusive team. We hire the best people based on an evaluation of their potential and support them throughout their time at Cloudflare. Come join us! 

Available locations: Lisbon or London

About Cloudflare and Our Team:

Cloudflare's Engineering Team is home to some of the industry's top engineers, dedicated to building and scaling innovative software that handles a significant portion of Internet traffic. Our team, specifically responsible for Turnstile and Challenge Pages, collaborates closely with a dedicated Product Manager and other engineering teams to develop cutting-edge bot detection and mitigation solutions. Our focus is on enhancing internet security while preserving user privacy and usability. Check out some of our articles mentioning Turnstile!

What You'll Do:

As a Machine Learning Engineer on our team, you'll play a key role in expanding our Turnstile and Challenge products. Your responsibilities will include:

• Advanced Bot Detection: Develop sophisticated bot and human detection capabilities using machine learning and traffic analysis techniques, with a strong emphasis on privacy and security.
• Full-Stack Development: Engage in full-stack development—from backend systems and distributed frameworks to client-side logic—to build comprehensive solutions.
• Scalable and Secure Software: Build scalable, secure, and privacy-conscious software to accommodate a growing and diverse user base.
• Cross-Functional Collaboration: Work closely with cross-functional teams to innovate and enhance our security solutions.
• Research and Development: Contribute to research efforts, potentially publishing findings in security and privacy conferences.

About You:

We're looking for a motivated individual with:

• Strong Background in Machine Learning and Security: Expertise in machine learning, distributed systems, and security, particularly in traffic analysis.
• Data Analysis Experience: Familiarity with data analysis frameworks like Spark and machine learning libraries such as Scikit-learn and PyTorch.
• Security-Focused Mindset: Essential for developing products like Turnstile that prioritize user privacy and security.
• Experience with Privacy Technologies: Knowledge of privacy-enhancing technologies and countermeasures.
• Curiosity and Drive: A natural sense of curiosity and a self-driven attitude to continuously learn and solve complex problems.
• Excellent Communication Skills: Strong problem-solving abilities and the capacity to communicate effectively within a team.

Bonus Points:

• Cloud and DevOps Tools: Experience with cloud platforms like GCP or AWS, Docker, Git, and distributed systems tools such as Terraform and Ansible.
• Database Knowledge: Familiarity with PostgreSQL and ClickHouse.
• Counter-Abuse Experience: Previous work in counter-abuse, fraud detection, and mitigation.
• Research Contributions: Publications or contributions to security and privacy research are highly regarded.

Working in Our Team:

You'll be integral to making our products more robust, secure, and stable. Our solutions run across the web on various browsers, requiring continuous testing and adaptability. We value innovation and problem-solving skills—we encourage you to identify challenges and propose effective solutions. Our team meetings focus on addressing these challenges, with an emphasis on delivering both short-term and long-term value to the business.

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: We equip politically and artistically important organizations and journalists 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: We created 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.

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!

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.