Software Engineer

About Us

At Cloudflare, we have our eyes set on an ambitious goal: to help build a better Internet. Today the company runs one of the world’s largest networks that powers more than 10 trillion requests per month. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare have all 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 recognized by the World Economic Forum as a Technology Pioneer and named to Entrepreneur Magazine’s Top Company Cultures list.

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!

What you'll do

You will work as part of our core engineering team in London which builds the Cloudflare system running in 160+ cities around the world. Your code will impact upwards of 2.8 billion people/month. Your work will focus on building robust, secure and high performance distributed systems. We are a small engineering team operating at massive scale, so what you do will have huge influence.

We work in agile teams, so you will be supported by colleagues, and collaborate with other teams around the company. Our London teams include:

Edge

Building a TLS/HTTP proxy, to make the connection from eyeball to edge as fast and secure as possible. Filtering malicious traffic and handling good traffic according to customers configuration. Projects include implementing QUIC, bot mitigation and content optimisation.

Services

Building Go APIs and React UIs to support feature configuration, and to retrieve data from the edge to provide analytics and insight APIs for those features.

Data

Crafting, building, and scaling one of the biggest global data pipelines to overcome network delays and partitions. Using Go, Kafka, ClickHouse, Flink and PostgreSQL to store and analyse in excess of 10 million events per second (and growing fast).

DNS

Maintaining our Authoritative DNS server and our public resolver 1.1.1.1. We like to be state of the art and roll out new standards features early like DNS-over-TLS.

L4/DDOS

Using core networking to stop DDoS at kernel or switch level. Creating detection and control systems for automatic reaction to attacks by analysing a large volume of real-time data. Managing and routing traffic at layer 4 to optimise our performance.

Quicksilver

Improving and operating our built-in house distributed key-value store. It stores over 600 million key-value pairs distributed over 50,000 Unix processes. Quicksilver is being accessed each time a request hits Cloudflare Edge. Quicksilver serves over 11 million request a second for a daily total exceeding 1 trillion.

This particular role is on one of our main Edge teams.  The team is responsible for developing and supp