Research Engineer Intern (Summer 2026)

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: Lisbon, Portugal About the department Cloudflare’s Research Team pursues strategic projects that have a large impact on Cloudflare systems and the Internet at large. Our focus is on solving difficult problems to connect and protect users, applications, and data, while helping to make the Internet more resilient, efficient, and transparent. In our quest to help make a better Internet, we frequently find ourselves exploring open problems at the boundaries of knowledge in scalable computing, with a focus on security and privacy, using techniques including AI/ML and performance analysis. We make cutting edge research contributions in-house, as well as in collaboration with academia, Internet standards organizations like the IETF, and more! Our team includes experts in many disciplines, including applied cryptography, privacy, network architectures and protocols, measurement, distributed systems, storage optimization, machine learning for systems, and more. We seek interns that augment our existing expertise as well as those who are working in broadly related areas. We have a vast set of potential projects focussed on our current priorities. We also welcome new ideas via concrete proposals that, more than just satisfying curiosity, may help to improve Cloudflare or aspects of the Internet and surrounding technologies touched by Cloudflare. We are, after all, researchers at heart and love learning, too! More information about Cloudflare's approach to research can be found here . What you'll do Cloudflare's Research Team solves difficult problems in security, privacy, and systems at scale. This involves engineering, data analysis, open source software development, protocol design, implementation of primitives, with lots of measurement alongside. Successful candidates will be matched to suitable projects in on-going research directions. We also welcome novel proposals and ideas that can help to inform or build a better Internet (in the form of a max 200 word proposal). The Internet is evolving in ways that challenge convention, and many existing assumptions no longer hold. Interns and internship projects are designed to help maintain the integrity of the Internet, its systems, and its applications. Some of the fundamental areas we’re investigating focus on include advanced cryptography, hardware isolation, balancing user privacy against notions of identity, network and internetwork observ ... (truncated, view full listing at source)