Senior Response Engineer - CMDC

Cloudflare; Greater London; On-site; GBP 90,000 - 140,000; Full time

Job summary

Cloudflare, London, is seeking a Response Engineer (Network Security) to lead advanced DDoS defense work at the edge. You will architect responses to sophisticated threats, guide incident remediation, and collaborate with AI teams to automate defenses.

The role requires deep routing protocol knowledge and 8+ years in security operations. Ideal candidates will engineer scalable mitigation strategies, tune detections, and mentor the Managed Defense Center while delivering high-visibility technical

Qualifications

• 8+ years in DDoS mitigation or network security incident response.
• Deep understanding of internet routing and encapsulation protocols (BGP, GRE).
• Experience designing robust mitigations for volumetric attacks at edge.
• Ability to design and tune detection rules with low false positives.
• Proficiency in Python/Go/Bash to automate workflows; AI/ML support a plus.
• Familiarity with monitoring platforms like Prometheus and Grafana; relevant certifications valued.

Responsibilities

• Lead incident response during large-scale DDoS events with edge-focused mitigations.
• Architect responses to threats, validate mitigation rules, ensure clean traffic via BGP/GRE.
• Design and tune network attack detections and security alerts.
• Collaborate with product, engineering, and AI teams to automate defenses.
• Communicate technical guidance to customer networks during incidents.
• Develop AI-driven troubleshooting playbooks and self-healing workflows.
• Mentor the Managed Defense Center team on advanced traffic analysis.

Skills

DDoS mitigation

Network security ops

BGP expertise

GRE encapsulation

TCP/IP analysis

Automation scripting

Monitoring tooling

Certifications knowledge

Tools

Prometheus

Grafana

Python

Go

Bash

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: London, United Kingdom

About the role

The Response Engineer (Network Security) - CMDC serves as a core technical specialist within the proactive security team. This position is built for a network security practitioner who thrives at the intersection of deep routing protocol investigation, edge-network defense, and strategic technical partnership. The role is responsible for architecting responses to sophisticated infrastructure threats across OSI Layers 3 and 4, ensuring global customers remain resilient against large-scale volumetric DDoS attacks and complex network-layer anomalies.

What you’ll do

• Technical Mentorship: Elevating the team’s collective skill set by acting as a “player-coach” providing hands‑on technical guidance during live incidents and reviewing complex mitigation strategies.
• Deep‑Dive Investigation & Mitigation: Analyzing infrastructure threats using advanced internal telemetry to engineer informed mitigation strategies—specifically focusing on DDoS vectors, BGP routing anomalies, and GRE encapsulation issues—implementing defenses directly on the edge for mission‑critical traffic.
• Detection Engineering & Tuning: Continuously designing and refining detection mechanisms, security controls, and alerting thresholds to ensure highly accurate, rapid identification of sophisticated network attacks with minimal false positives.
• Infrastructure & Tooling Evolution (AI-Driven): Partnering closely with Product, Engineering, and AI teams to transform real‑world DDoS attack data into AI‑powered automated network defenses, dynamic mitigation models, and enhanced platform capabilities.
• Strategic Technical Communication: Serving as an authoritative technical voice during active volumetric attacks, providing clarity and architectural routing guidance to both internal stakeholders and external customer engineering teams.

The ideal candidate moves beyond following static runbooks to engineering AI‑assisted response workflows, transforming raw network flow telemetry into actionable mitigation strategies, tuned detections, and intelligent, automated edge defenses.

Responsibilities

• Technical Escalation & Response: Acting as a subject matter expert for the Managed Defense Center during complex network security incidents, providing hands‑on intervention for large‑scale volumetric and protocol‑based DDoS attacks when standard protocols are exceeded.
• Incident Architecture: Leading the technical response to sophisticated infrastructure threats, validating the efficacy of network mitigation rules, and ensuring stable, clean traffic delivery via BGP and GRE mechanisms.
• Detection Engineering: Designing, deploying, and tuning network attack detection logic, utilizing attack telemetry to stay consistently ahead of evolving DDoS methodologies and adversary tactics.
• Technical Communications: Driving high‑touch technical dialogue with customer network teams during critical incidents, translating complex routing and attack flow data into actionable architectural advice.
• Operational Engineering & AI Integration: Designing and refining technical Managed Defense workflows, building AI‑driven automated troubleshooting playbooks (particularly around BGP/GRE), and tuning alerting thresholds to create self‑healing infrastructure responses.
• Forensics & Analysis: Utilizing internal telemetry, flow data, and specialized monitoring tools to perform deep‑dive forensics on novel network attack vectors.
• Technical Coaching: Mentoring the Managed Defense team on advanced traffic analysis and security best practices, ensuring a high technical bar across the Managed Defense Center.

Desirable Skills, Knowledge, and Experience:

• Experience : A minimum of 8+ years of relevant hands‑on experience specifically within the DDoS mitigation industry, Network Security Operations, or a highly technical infrastructure incident response environment.
• Protocol Sovereignty: A profound understanding of internet routing and encapsulation protocols. Expert‑level knowledge of BGP (Border Gateway Protocol) and GRE (Generic Routing Encapsulation) reinjection, along with a deep ability to deconstruct TCP/IP, UDP, and ICMP traffic flows.
• Security Mastery: Proven ability to identify common network attacks and design robust mitigation strategies for complex volumetric DDoS, UDP/TCP based, and protocol exhaustion using edge‑based security controls.
• Detection & Tuning: Demonstrated expertise in detection engineering, including the continuous tuning of network security rules and alerts to optimize defense efficacy and operational signal‑to‑noise ratios.
• AI Tooling & Automation: Proficiency in Python, Go, or Bash to automate network security workflows, with demonstrated experience leveraging AI/ML models or LLM APIs to build automated troubleshooting diagnostics and dynamic threat mitigations.
• System Literacy: Experience with monitoring platforms (e.g., Prometheus/Grafana) and querying large network datasets to operationalize contextual routing and security data.
• Certifications : Advanced networking and network security credentials such as Cisco CCNP, CCNP Security, or CCIE are highly valued.

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 released1.1.1.1 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.

Please note that applicants who progress to the offer stage of the interview process may be asked to attend an in-person interview within one of the Cloudflare Offices or Cloudflare Hubs. More details about this will be available at that stage of the interview process.

This position may require access to information protected under U.S