Senior Software Engineer, Workers Runtime · Cloudflare

Sun, 26 Apr 2026 15:44:50 GMT
Engineering

Cloudflare · Hybrid · hybrid

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.

We protect and accelerate 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.

Available Locations:

Austin, TX | Lisbon, Portugal | London, UK

About the Department

Emerging Technologies & Incubation (ETI) is where new and bold products are built and released within Cloudflare. Rather than being constrained by the structures which make Cloudflare a massively successful business, we are able to leverage them to deliver entirely new tools and products to our customers.

Cloudflare’s edge and network make it possible to solve problems at massive scale and efficiency which would be impossible for almost any other organization.

About the Team

The Workers Runtime team delivers features and improvements to our Runtime which actually executes customer code at the edge. We care deeply about increasing performance, improving JS API surface area and compiled language support through WebAssembly, and optimizing to meet the next 10x increase in scale.

The Runtime is a hostile environment - System resources such as memory, cpu, I/O, etc need to be managed extremely carefully and security must be foundational in everything we do.

What you'll do

We are looking for a Systems Engineer to join our team. You will work with a team of passionate, talented engineers that are building innovative products that bring security and speed to millions of internet users each day.

You will play an active part in shaping product features based on what’s technically possible. You will make sure our company hits our ambitious goals from an engineering standpoint.

You bring a passion for meeting business needs while building technically innovative solutions, and excel at shifting between the two,understanding how big-picture goals inform technical details, and vice-versa.

You thrive in a fast-paced iterative engineering environment.

Examples of desirable skills, knowledge and experience

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

Solid understanding of computer science fundamentals including data structures, algorithms, and object-oriented or functional design.

An operational mindset - we don't just write code, we also own it in production.

Deep understanding of the web and technologies such as web browsers, HTTP, JavaScript and WebAssembly.

Experience working in low-latency real time environments such as game streaming, game engine architecture, high frequency trading, payment systems.

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

Bonus Points

Experience building high performance distributed systems in Rust.

Experience working with cloud platforms, especially server-less platforms.

Experience with the internals of JS engines such as V8, SpiderMonkey, or JavaScriptCore.

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

Deep Linux/UNIX systems, 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 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.