Senior Security Engineer- UK

About the Role Hopper's Security team is small by design and consequential by impact- and this role sits at the centre of it. As a Senior Security Engineer, you'll own the tooling, automation, and processes that keep our applications secure across their entire lifecycle, building the systems that make security invisible to developers and unavoidable by default. This is a builder's role in every sense: you'll write code, ship tools, and use AI as a core part of how you work — not as a novelty, but as a force multiplier. What would your day-to-day look like - Own and evolve our vulnerability management program with a focus on application security — container images, dependencies, code scanning, and runtime detection - Build and maintain security tooling that integrates directly into CI/CD pipelines and developer workflows, so security happens automatically rather than as a gate - Use AI extensively to write code faster, automate analyses that would otherwise require manual review, and build intelligent tooling that scales beyond what a small team could achieve manually - Assess and improve how we leverage available telemetry across our systems - Work directly with engineering teams to influence secure development practices — not by writing standards and documents, but by shipping tools and defaults that make the secure path the easy path - Investigate and respond to security findings when needed, but spend more of your time building systems that prevent and detect issues than manually chasing them - Adapt quickly as priorities shift — our team is agile and tomorrow's challenge may look different from todays An ideal candidate has - At least 5 years experience software and/or platform engineering, with the ability to design, build, and maintain production-quality tools - Deep experience in application security and vulnerability management — you understand CVEs, dependency risks, container security, and SDLC integration, and you have opinions about what's worth fixing and what's noise - Hands-on experience with cloud infrastructure, ideally GCP/GKE or equivalent, with the ability to adapt to our stack - A demonstrated habit of using AI tools — coding assistants, LLMs — as a core part of how you build and analyse, not an occasional shortcut - A bias toward automation — when you see a repetitive manual task, your instinct is to write a tool, not a runbook - Comfort with ambiguity and ownership — you'll often be the only person on a problem and will need to make judgment calls on priority, approach, and scope without waiting for direction - Experience influencing engineering culture around security, knowing how to make developers care without slowing them down - Strong written and verbal communication skills, including the ability to articulate our security posture clearly to customers when needed Perks and benefits of working with us - Well-funded and proven startup with large ambitions, competitive salary, upsides of pre-IPO equity packages. - Hopper covers 100% of the premiums for the employee for a group insurance plan through Vitality Health. - Automatic contributions when you start with Hopper through Smart Pension. - Please ask us about our very generous parental leave, much above industry standards!. - Access to co-working space on demand through FlexDesk AND Work-from-home stipend. - Carrot Cash travel stipend. - Unlimited PTO. - Entrepreneurial culture where pushing limits and taking risks is everyday business. - Open communication with management and company leadership. - Small, dynamic teams = massive impact. More about Hopper At Hopper, we are on a mission to become the leading travel platform globally – powering Hopper’s mobile app, website and our B2B business, HTS (Hopper Technology Solutions). By leveraging massive amounts of data and advanced machine learning algorithms, Hopper combines its world-class travel agency offering with proprietary fintech products to bring transparency, flexibility and savings to traveler