Senior/Lead Security Engineer (Detection & Response)

Fuse is an AI-first energy company on a mission to make energy abundant and affordable, fast. We combine first-principles thinking with cutting-edge technology to build a radically better energy system. We've raised over $200M from top-tier investors including Balderton, Lakestar, Accel, Creandum, Lowercarbon, Ribbit, 20VC, Hummingbird and Collaborative Fund, alongside strategic angels including Nico Rosberg and GPs behind Meta, Revolut, Spotify and Uber. We're building a fully integrated energy company: developing our own solar, batteries and other generation projects, building our own hardware, improving and developing grid infrastructure, trading power in real time, and installing distributed energy in homes. By selling directly to consumers, we cut out the middleman, lower costs and pass the savings on to our customers. About the role We're looking for a Senior or Lead Security Engineer (Detection & Response) to build out the next generation of detection systems. You'll sit within the team responsible for security across our IT and cloud environment, spanning AWS, identity, endpoints, SaaS and data center infrastructure. You'll own security monitoring and detection end-to-end: anticipating how our systems could be compromised, ensuring we have the right telemetry to see it, and building the detections and response workflows to act on it. Think of it like SRE for security. We want someone who can answer questions like: Has this account been compromised? Is someone accessing AWS who shouldn't be? Has an attacker moved laterally through our network? How would we know? You'll also lead investigations and incident response, automate repetitive security work, and work with IT and Engineering to fix the underlying problems you uncover. Responsibilities • Own security monitoring and detection across AWS, identity, endpoints, SaaS, networks and data center environments • Build and maintain the telemetry and logging pipelines needed to detect security incidents, and continuously test and improve detection coverage • Lead security investigations and incident response from detection through containment, recovery and post-mortem • Proactively hunt for threats and identify gaps in our visibility, controls and detection coverage • Build automation to improve detection, investigation and response, making effective use of AI and emerging tools to improve efficiency and capabilities. • Work closely with IT and Engineering to turn security findings into preventative controls and better system design • Develop and test incident response playbooks and continuously improve our response capability • Implement and enhance internal AI agents and security bots that assist with monitoring, investigations, reporting, and other security operation tasks. Requirements • Significant hands-on experience in detection engineering, security engineering, incident response, threat hunting or a similar technical role • Strong understanding of cloud environments, ideally AWS, and how to monitor them for unauthorised or suspicious activity • Strong networking fundamentals and an understanding of how attackers move through networks and systems • Strong understanding of attacker tradecraft and the ability to turn it into useful, high-signal detections • Experience investigating real security incidents and taking ownership through to resolution • Strong scripting or programming skills, ideally Python, and a habit of automating repetitive work • Experience with security monitoring and response tooling such as SIEM, EDR, SOAR or equivalent • Strong systems thinking and a natural instinct for asking “how would we know if this was compromised?” • Comfortable working autonomously and closely with IT and Engineering teams • Curious about emerging AI capab