Staff Security Engineer (Application Security)

Join WRITER, a leading AI platform, as a Staff Security Engineer specializing in application security. 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 tackle unique challenges in AI security. This hybrid position is based in New York City, San Francisco, or Seattle, and offers a range of benefits including health coverage, parental leave, stock options, and a learning and development stipend.

• 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.

• 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
• 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
• 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
• Minimum 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
• 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)
• Understanding of developer experience and developer workflows for shipping features and products. You care deeply about reducing risk while considering velocity of engineers
• *This role is open to Mid, Sr. and Staff level candidates