Senior Software Engineer - London & Lisbon

Available locations: Lisbon or London
Hiring Process & Cloudflare's Engineering Teams
If you want to build things at Cloudflare but are unsure about which team to apply for, this role will give you the best opportunity to match with a team that is most aligned to your experience, skill, and ambition. We've created a hiring process designed to find great candidates and figure out where they fit best as we go along. At the end of the hiring process you will have the opportunity to meet with one or more teams to find out if there is a fit, but if you discover during the interview process that a particular team or product area is interesting to you let us know.
About Engineering at Cloudflare
Cloudflare's Engineers build and operate the software that helps power 25+ million Internet properties and millions of businesses around the world. Across our engineering organizations, we have opportunities for high caliber, curious and empathetic people to take on big challenges and build some of the best skills in the industry. We're looking for talented team members to help build high-growth products, help scale our expanding network, build tools to improve availability, performance, uptime, and response times, and make systems failure-resistant and ready-to-scale.
Cloudflare is a system spanning the globe, on a mission to make the Internet better, safer, and more powerful every day. As a Software Engineer at Cloudflare, you'll work on the code that runs close to the end user, runs at a massive scale, and is deployed to 330+ cities around the world.
Examples of software systems at Cloudflare:
Since we don't know what team you'll be working on quite yet, here's some things that we do at Cloudflare. This is not a complete list, but gives a good indica
tion of the wide variety of things you might work on.

• 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 customer configuration
• Content optimization that takes content served from customer sites and makes it more performant
• A platform that runs "serverless" Workers and provides a key value store
• A reverse-proxy system that caches customer website content according to customer configuration
• Optimization of connections from Cloudflare to our customers' origin servers to reduce their load and increase performance
• Our Authoritative DNS server and our public resolver 1.1.1.1.
• Data Science diving deep into HTTP request data, identifying malicious and fraudulent traffic patterns, and building novel solutions for mitigating such attacks.
• Full Machine Learning platform and model development, from feature engineering to model development to release and monitoring.
• One of the biggest data pipelines in the world, operating at well over 250M events per second
• We operate some of the fastest, and most widely distributed services on the Internet. Your work will focus on building robust, secure, and high performance distributed systems. We are a small engineering team operating at a massive scale, so what you do will have a huge impact.

Requirements for any role
If you think some of this list describes you (or what you aspire to be) we would love to talk to you. While not listed as a requirement, we also want to call out that most roles need the flexibility to be on-call outside of standard working hours to address technical issues as needed.

• First and foremost curiosity and critical thinking
• Experience (and love for) debugging to ensure the system works in all cases
• Experience with a continuous integration workflow and using source control (we use git)
• Designing and building APIs
• Understanding of what it takes to build secure systems
• Confidence to work in multiple programming languages - bonus points for Go and/or Rust

Examples of desirable skills, knowledge and experience
Some team-specific things we think are interesting and want to highlight.

• Understanding systems at the network protocol level, including the differences between what the specs say, and what actually happens on the Internet
• Strong systems level programming skills
• Optimization of complex solutions
• Experience with databases (we use PostgreSQL and Clickhouse)
• Understanding what it takes to build and maintain distributed systems
• Good Unix knowledge, having submitted patches to Operating Systems a huge plus for some roles
• Experience with monitoring, alerting and debugging high volume production systems
• Fluent in analyses of data sets such as logs
• Understanding of security and fraud detection systems