Senior Software Engineer, Durable Objects (DO)

Confirmed live in the last 24 hours

Cloudflare

Hybrid

Posted February 6, 2026

Job Description

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: 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, an

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