Senior Software Engineer, Workers Runtime

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, TX

About the Role

Cloudflare’s Emerging Technologies & Incubation team builds new products at the edge by combining Cloudflare’s network scale with rapid product incubation. This role is on the Workers Runtime team, which ships the runtime that executes customer code at the edge. You’ll improve performance, expand JavaScript and WebAssembly support, and help the runtime scale safely and efficiently.

Responsibilities

Build features and improvements for the Workers Runtime.

Improve runtime performance, reliability, and scale.

Expand JavaScript API and WebAssembly support.

Help shape features based on what is technically possible.

Own code in production and debug issues in a large-scale distributed system.

Work in a fast-paced, iterative environment that balances product goals with technical execution.

Desirable Skills, Knowledge & Experience

2+ years of recent professional experience with C++ or Rust.

Strong computer science fundamentals, including data structures, algorithms, and software design.

Operational mindset and experience owning production systems.

Deep understanding of the web, including HTTP, JavaScript, and WebAssembly.

Experience debugging and optimizing large-scale Linux-based distributed systems.

Bonus Points

Experience building high-performance distributed systems in Rust.

Experience with cloud or serverless platforms.

Familiarity with JS engine internals such as V8, SpiderMonkey, or JavaScriptCore.

Experience with standalone WebAssembly runtimes such as Wasmtime, Wasmer, or Lucet.

Deep Linux, UNIX, kernel, or networking knowledge.

Contributions to large open source projects.

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 inf