Application Security Engineer

Join WRITER, a leading AI platform, as an Application Security Engineer. In this role, you will build the security foundations that protect our AI systems, partner with engineering teams to embed security into every line of code, and help define how enterprise AI applications are secured. You will work in a hybrid environment from our London office and report to the head of security engineering.

• Concevoir et recommander des fonctionnalités et des produits de sécurité pour aider à sécuriser les environnements des clients.
• Diriger les évaluations de sécurité et les tests de pénétration des applications, des services d'IA et des API de WRITER.
• Construire la sécurité dans l'ADN de notre plateforme d'IA en menant des sessions de modélisation des menaces avec les équipes produit.
• A builder's mindset that looks for opportunities to automate, scale, and empower rather than create bottlenecks—you understand that security enables the business, not blocks it
• 4+ years of hands-on experience in application security engineering, with a proven track record of securing large-scale production systems—bonus points if you've worked in fast-growing startups or high-growth environments
• Understanding of developer experience and developer workflows for shipping features and products. You care deeply about reducing risk while considering velocity of engineers
• Excellent communication skills that allow you to translate complex security concepts into clear recommendations for both technical and non-technical audiences—you can explain why something matters and motivate teams to action
• Knowledge of security tools and methodologies including SAST/DAST solutions, vulnerability management platforms, security testing frameworks, and DevSecOps practices—you know which tools to use and when automation beats manual review
• Alignment with WRITER's values of Connect (building strong relationships across teams), Challenge (pushing the boundaries of what's possible in AI security), and Own (taking end-to-end responsibility for the security of our platform)
• Technical expertise in at least two programming languages (Python, Java, Go, JavaScript/TypeScript) and the ability to read and review code across multiple languages, understanding both business logic and security implications