Application Security Engineering Manager

Location: Europe remote or London hybrid About the role:

As our engineering and research organisation grows, so does the complexity of securing it. Our Application Security team is at the forefront of that challenge — building AI-native security tooling, embedding security into the development lifecycle at scale, and finding ways to make a small, highly capable team punch well above its weight.

We're looking for an Engineering Manager to lead and grow the App Sec team. This is not a coordination role. You’ll be leading a team of exceptionally senior and staff-level engineers who are deeply self-directed and technically excellent. To earn their trust and enable their best work, you need to be genuinely close to the craft — able to engage at depth on threat modelling, agentic security tooling, SDLC design, and application risk.

You’ll also own App Sec strategy and be accountable for how the function scales alongside a product organisation that is growing fast and leaning heavily into AI-assisted development.

Important note:

Anyone working as a manager within the Infosec team will need to follow the Infosec Team Management Tenets.

• Lead, support, enable and grow the App Sec team — owning hiring, onboarding, performance, and career development for a team of Senior and Staff-level Security Engineers. We need someone to enable the team to do what needs doing and to give them the best possible environment.
• Own the formalisation of App Sec strategy and roadmap, translating team input, business risk and engineering context into a clear, prioritised programme of work with measurable outcomes.
• Be a credible technical partner to your team — engage substantively on threat models, security architecture, agentic tooling design, and risk decisions, and be willing to get into the details when it matters.
• Define and maintain the team's operating rhythm: OKRs, quarterly planning, cross-team coordination, and stakeholder communication up to leadership.
• Act as a key interface between App Sec and the rest of the organisation and leadership — build relationships with business leadership, engineering leads, the Developer Platform team, Architecture Working Group, and partner functions like Legal and Moderation, to embed security into how Synthesia builds.
• Participate in maintaining and evolving Synthesia's approach to AI-assisted development security, including how we secure our own use of agentic coding tools and how we assess the security of AI-generated code.
• Own App Sec's relationship with the broader Security function, ensuring tight alignment between App Sec and other Infosec teams on shared risks, incidents, and cross-cutting initiatives.
• Represent App Sec externally where relevant — with customers, auditors, and in the context of compliance programmes such as SOC2 and ISO 42001.

• Lead a small, senior team with high autonomy, focusing on creating leverage rather than running a ticket queue.
• Work in a leading AI company with high growth and a very friendly culture — it’s a fun ride.
• Build and ship AI-native/agentic security tooling end-to-end, from prototypes to production systems that materially change how engineering works.
• Operate at the intersection of product, platform, and security architecture, with scope to shape how secure-by-default looks in a rapidly scaling AI company.

You’re a Security Engineer first, who has grown into leadership. You’re comfortable in the details and know when to roll up your sleeves, but you’ve also developed the organisational instincts to run a team effectively and the strategic clarity to own a function.

• You’re a strong communicator who can operate across audiences — from deeply technical discussions with staff engineers, to clear risk framing for leadership, to pragmatic negotiation with product and engineering partners.
• You have a strong engineering background in application security, with hands‑on experience in areas such as threat modelling, secure design review, (AI‑)SAST/SCA tooling, vulnerability management, and/or security automation.
• You are very comfortable with Python and JavaScript. You have experience with AWS…