Senior Software Engineer, Durable Objects (DO)

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 : Austin, Texas | Lisbon, Portugal | London, UK

About the Department

Cloudflare's Emerging Technologies & Incubation (ETI) team is where bold, innovative products are built and launched. Rather than being limited by the structures of a large, established business, we leverage Cloudflare's global edge network to solve problems at an unparalleled scale and efficiency .

What You'll Do

In this role, you will build Durable Objects , the Cloudflare Developer Platform's product for building stateful serverless applications . As a member of this top-notch systems engineering team, you will design and develop the low-level routing and storage systems that power Cloudflare's customers' ability to build and scale. Your job is to drive the continual evolution of the system which improves reliability, performance, and provides new features. For a recent summary of these changes take a look at this.

As a key engineer on this team, you will :

Build the Durable Objects runtime which enables Cloudflare customers to build real-time chat applications, multiplayer games, and AI agents.

Improve reliability, scalability, and performance by developing new system capabilities.

Own your code end-to-end from design to production.

Solve complex technical challenges with production distributed systems.

Develop software in JavaScript, TypeScript, Rust, and C++.

What We're Looking For

5+ years of experience writing systems software.

Operational mindset - we don't just write code, we own it in production.

Strong foundation in data structures, algorithms, and system design.

Deep expertise in at least one systems programming language (e.g., C / C++ or Rust).

Experience designing and architecting large-scale distributed systems .

Familiarity with cloud platforms, particularly serverless architectures.

Experience as a technical leader or team lead , driving engineering decisions.

Bonus Points

Experience working on database internals (specifically SQLite).

Deep understanding of web technologies (browsers, HTTP, JavaScript, WebAssembly).

Background in low-latency, real-time environments (e.g., game streaming, high-frequency trading, payment systems).

Experience debugging, optimizing, and identifying failure modes in large-scale Linux-based distributed systems.

This is a high-impact role for engineers who thrive in fast-paced, distributed environments and want to shape the future of cloud computing . If that sounds like you, we'd love to hear from you!

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.

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