Application Security Engineer

Fin is the AI Customer Agent company on a mission to help businesses provide perfect customer experiences.

Our AI Agent Fin is the highest-performing AI Customer Agent on the market today, enabling businesses to deliver impeccable, always-on customer support across the customer journey – from service, to sales, to ecommerce.

The Application Security Engineer will own and engineer tier-zero security capabilities that help customers securely deploy and manage Fin.

Responsibilities

• Design, build, and evolve customer-facing security features, including authentication, SAML/SSO, permissions systems, audit and activity logging, malicious URL scanning, and other enterprise security controls.
• Partner with engineering teams throughout the software development lifecycle to build secure products and services.
• Perform architecture reviews, threat modelling exercises, and security assessments for new features and systems.
• Build security tooling, automation, and developer-facing building blocks that make secure development easier and more scalable.
• Contribute to secure development standards, guidance, and best practices across Fin.
• Lead application security initiatives across the software development lifecycle, helping teams identify and address security risks early.
• Participate in a shared on-call rotation and lead security incident response, investigation, and remediation efforts.
• Drive security initiatives from problem definition through design, implementation, and measurable outcomes.
• Partner with teams building AI-powered products to assess and mitigate emerging security risks.
• Help shape Fin's AI-first approach to security, including AI-powered detection, red-team automation, continuous monitoring, and emerging defensive capabilities.
• Support the secure adoption of AI-assisted software development tools and engineering workflows.

Requirements

• Proven application security, product security, or security engineering experience within a SaaS environment.
• Strong software engineering skills with experience designing, building, and operating production systems.
• Deep understanding of modern application security threats, secure software development practices, and threat modelling.
• Experience designing, building, or securing authentication, authorization, identity, or enterprise security capabilities.
• Experience conducting architecture reviews and security assessments for complex systems.
• Hands-on security incident response experience, including leading investigations and remediation efforts.
• Strong programming skills and experience building tools, automation, or developer-focused solutions.
• Comfortable using modern AI-assisted development tools to improve productivity and engineering effectiveness.
• Ability to communicate security concepts clearly and collaborate effectively with engineering teams.
• A pragmatic approach to balancing security, customer impact, and engineering velocity.

Nice to Have

• Experience building or owning authentication, SAML/SSO, identity, or access management capabilities.
• Experience securing AI-powered products or familiarity with security considerations for large language models, agentic systems, retrieval-based architectures, or AI tool integrations.
• Experience building security automation or security-focused platform capabilities at scale.
• Familiarity with cloud security, infrastructure security, or distributed systems.
• Experience working across both large-scale SaaS environments and high-growth companies.

Benefits

• Competitive salary and equity in a fast-growing start-up
• We serve lunch every weekday, plus a variety of snack foods and a fully stocked kitchen
• Regular compensation reviews - we reward great work!
• Unlimited access to Claude Code and best-in-class AI tools; experimentation & building is encouraged & celebrated.
• Pension scheme & match up to 4%
• Peace of mind with life assurance, as well as comprehensive health and dental insurance for you and your dependents
• Flexible paid time off policy
• Paid maternity leave, as well as 6 weeks paternity leave for fathers, to let you spend valuable time with your loved ones
• If you're cycling, we've got you covered on the Cycle-to-Work Scheme. With secure bike storage too
• MacBooks are our standard, but we also offer Windows for certain roles when needed.