Security Engineer (Application Security)

Join WRITER, a leading AI platform, as a 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 help define how enterprise AI applications are secured. You will work in a hybrid environment from our San Francisco or New York City offices and report to the head of security engineering.

• Conduct threat modeling sessions with product teams, design secure architectures for new features, and ensure security considerations shape product decisions from day one.
• Own and evolve the application security program, including establishing and maintaining SAST/DAST scanning in CI/CD pipelines, conducting security code reviews, and building automation that catches vulnerabilities.
• Partner with engineering teams to establish and champion secure coding standards, creating reusable security patterns and libraries that make it easier for developers to build securely by default.
• *This role is open to Mid, Sr. and Staff level candidates
• 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
• Understanding of developer experience and developer workflows for shipping features and products. You care deeply about reducing risk while considering velocity of engineers
• 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
• 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
• 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
• 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)
• 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