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Senior Software Engineer - Quicksilver - Distributed Key Value

Cloudflare, Inc.
United States, California, San Francisco
101 Townsend Street (Show on map)
Oct 27, 2025
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. 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: London, Amsterdam, Lisbon, Austin What you'll do/ responsibilities Quicksilver is Cloudflare's globally distributed key-value store. It replicates our data all around the world, over tens of thousands of servers and over 500 data centers. It handles all kinds of network conditions and serves billions of keys per second.In this role, you can expect to seechallenges like unexpected network issues, hardware failures, kernel bugs and still have to deliver the data to the edge in a fast and reliable way. Along with the rest of the team,you will own and support the whole stack: the code base, the unit and integration test, deployment and rollback plans, operations, monitoring, alerting, debugging and on-call.Quicksilver is written in Go and C.If working at this scale excites you and you are intrigued by very tricky bugs, rather than being scared by them, you might be a match for this role. Your daily duties will be: Working on our distributed large scale key-value store, you will write new features in Go and reviewing pull request Improving performance, CPU, memory usage, etc. Improving our monitoring and our tools, all written in Go Help with debugging and investigating hard to reproduce problems Requirements You have previous experience writing robust systems, code quality, performance and technical debt. You understand the tradeoffs that doing rigorous engineering requires. You have proven experience with storage systems, peer to peer systems, large scale distributed systems or simply system programming in general. You have previous experience of chasing problems through multiple layers of our software stack. You can be flexible and you are very curious. You are flexible and very autonomous. You won't be micromanaged in this role and will be looked to have experience thinking out of the box and coming up with simple and smart designs for complex issues. You have a previous track record of being pragmatic and believe in the value of simple solutions. You equally enjoy low-level and high-level programming. You have a taste for programming languages. You enjoy being a part of a team that challenges each other's designs -- you are good at taking and giving constructive criticism with a goal of producing the best solution. You are not afraid of engaging in outages on anti-social hours. 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: Since 2014, we've equipped more than 2,400 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 Cloudflare's 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, we've 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. 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.