Research Engineer Intern (Fall 2026)

Available Locations: Lisbon Portugal

About the department

Cloudflares 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 Cloudflares approach to research can be found here.

What youll do

Cloudflares 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 are particularly interested in applications in the following areas:

• AI
• Distributed Systems
• Privacy
• Trusted Execution Environments

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 were investigating focus on include advanced cryptography hardware isolation balancing user privacy against notions of identity network and internetwork observability in a seemingly fragmented world even applications of formal methods at scale and this is just a small view into our work! Were also acutely aware that AI will impact all layers of a globally distributed system and the wider Internet.

General Research Intern Requirements

• Evidence of tackling hard or open-ended problems
• Proven track record of peer-reviewed research open-source software contributions or standards development that is commensurate with level of training --- students at all levels are welcome to apply
• Experience clearly communicating research ideas through papers pre-prints standards documents blogs or similar media
• Ability to work in a systems-level programming language (e.g. Rust C Go)
• Passion for debugging and ensuring system reliability
• Familiarity with continuous integration workflows and source control systems (e.g. Gitlab Github)
• Willing and eager to share knowledge with the skills to do so

Additional Requirements

Knowledge or experience with at least one of the following:

• Computer networking protocols (TCP/IP DNS BGP QUIC etc.) and related algorithms
• Machine learning analysis ideally in systems or network optimization
• Authentication protocols applied cryptography PKI and SSL/TLS
• Operating or distributed systems analysis or development
• Measurement for network and computer systems
• Proficiency in a scripting language such as Python

Bonus Points:

• Proven track record of independently driving projects in a fast-paced environment
• Experience working in groups or with multiple stakeholders
• Able to fluently work across multiple programming languages

Internship Availability and Expectations:

• Ability to commit to a 12 week fall internship
• In office 3-4 days a week in Lisbon Portugal

What Makes Cloudflare Special

Were not just a highly ambitious large-scale technology company. Were 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 weve equipped more than 2400 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 Cloudflares 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 weve 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. Heres the deal - we dont 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 youd like to be a part of Wed 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 persons 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 or via mail at 101 Townsend St. San Francisco CA 94107.