Security Engineer, Application Security

Stack

Responsibilities

• ▹Conduct threat modeling sessions with product teams, design secure architectures for new features, and shape product decisions with security in mind from day one
• ▹Own and evolve the application security program: establish and maintain SAST/DAST scanning in CI/CD pipelines, conduct security code reviews, build automation that catches vulnerabilities early
• ▹Partner with engineering teams to establish secure coding standards, creating reusable security patterns and libraries
• ▹Design and recommend security features and products that help secure customer environments
• ▹Integrate and leverage AI agents to increase velocity for the security team and the broader engineering org
• ▹Lead security assessments and penetration testing of WRITER's applications, AI services, and APIs, remediating issues at scale
• ▹Design and implement security controls for data pipelines, model training environments, and customer-facing AI agents
• ▹Stay ahead of emerging threats in the AI/ML security landscape, researching LLM- and genAI-specific attack vectors

Requirements

• ▹Minimum 4 years of hands-on experience in application security engineering, securing large-scale production systems
• ▹Understanding of developer experience and workflows, balancing risk reduction with engineering velocity
• ▹Technical expertise in at least two programming languages (Python, Java, Go, JavaScript/TypeScript), able to review code across languages
• ▹Knowledge of security tools and methodologies: SAST/DAST solutions, vulnerability management platforms, testing frameworks, DevSecOps practices
• ▹Excellent communication skills for translating complex security concepts to technical and non-technical audiences
• ▹A builder's mindset that looks for automation, scale, and empowerment rather than bottlenecks

Nice to have

• ▹Experience in fast-growing startups or high-growth environments

Soft skills

What we offer

• ▹Generous PTO, plus company holidays
• ▹Medical, dental, and vision coverage for you and your family
• ▹Paid parental leave for all parents (16 weeks)
• ▹Fertility and family planning support
• ▹Early-detection cancer testing through Galleri
• ▹Flexible spending account and dependent FSA options
• ▹Health savings account with company contribution
• ▹Annual wellness and learning & development stipends
• ▹Company-wide and team off-sites
• ▹Competitive compensation, stock options, and 401k

About the company

WRITER builds the platform that lets the world's leading enterprises orchestrate AI-powered work, with a mission to expand human capacity through superintelligence. Its trustworthy, enterprise-grade LLMs and AI agents power companies like Mars, Marriott, Uber, and Vanguard. Founded in 2020 and valued at $1.9B, backed by investors including Premji Invest, Radical Ventures, and ICONIQ Growth, WRITER has office hubs in San Francisco, New York City, Seattle, Austin, Chicago, and London. This hybrid role is based out of the New York City, San Francisco, or Seattle offices, reporting to the head of security engineering.