Security engineer, application security

🚀 About WRITER
WRITER is at the forefront of orchestrating AI-powered work for the world's leading enterprises. Our audacious vision is to expand human capacity through superintelligence, and we're making it a reality. We deliver powerful, trustworthy AI that unites IT and business teams, unlocking enterprise-wide transformation.
With WRITER's end-to-end platform, hundreds of global brands like Mars, Marriott, Uber, and Vanguard are building and deploying intelligent AI agents. These agents are rigorously grounded in their company's data and fueled by WRITER's enterprise-grade Large Language Models (LLMs). Valued at $1.9B and backed by industry-leading investors including Premji Invest, Radical Ventures, and ICONIQ Growth, WRITER is rapidly cementing its position as the undisputed leader in enterprise generative AI.
Founded in 2020 with thriving office hubs in San Francisco, New York City, Austin, Chicago, and London, our team thrives on big ideas and fast execution. We're seeking smart, hardworking builders and scalers to join us on our journey to create a better, more intelligent future of work with AI.

🔐 The Opportunity: Security Engineer, Applications
This isn't just a security role; it's an invitation to define the future of AI security at an unprecedented scale. As an Application Security Engineer at WRITER, you'll build the critical security foundations that protect the cutting-edge AI systems powering some of the world's most recognizable brands. You’ll operate at the dynamic intersection of application security, advanced AI infrastructure, and crucial developer enablement.
Forget traditional "no" responses. This is about finding creative, ingenious ways to say "yes, and here's how we secure it." You'll partner deeply with engineering teams, embedding robust security into every line of code and every architectural decision, ensuring our platform remains both powerful and inherently trustworthy. The challenge is immense, and the impact will be global: you will shape how enterprise AI applications are secured, from groundbreaking threat modeling of our LLM architectures to designing and implementing automated security controls that scale across our rapidly expanding platform.
You'll tackle unique security challenges that most engineers never encounter: securing sophisticated AI agents, safeguarding sensitive training data pipelines, and designing controls for entirely new categories of systems that didn't exist just a few years ago. This role offers the flexibility of being remote within the US or hybrid from our San Francisco or New York City offices, reporting directly to the Head of Security Engineering.

🌟 What You'll Delive

**Architect Secure AI Systems:** Embed security into the very DNA of our AI platform. Lead threat modeling sessions with product teams, design secure architectures for new features, and ensure security considerations are integral to product decisions from day one, not an afterthought.
**Scale Application Security:** Own and evolve our comprehensive application security program. This includes establishing and maintaining advanced SAST/DAST scanning within CI/CD pipelines, conducting rigorous security code reviews for critical changes, and building intelligent automation to proactively catch vulnerabilities before they ever reach production.
**Empower Developers:** Champion secure coding standards and cultivate a security-first culture across engineering. Create reusable security patterns and libraries that empower developers to build securely by default, enhancing both velocity and resilience.
**Secure Customer AI Environments:** Design and recommend innovative security features and products that elevate the protection of our customers' AI environments. You will be the visionary advocate for how we secure and protect our customers' most valuable assets.
**Automate Security with AI:** Integrate and leverage AI agents to significantly increase the velocity and efficiency of the security team and the broader engineering organization, ensuring proactive risk minimization as we rapidly build new products.
**Lead Security Assessments:** Orchestrate and execute security assessments and penetration testing of WRITER's applications, AI services, and APIs. Identify vulnerabilities across our entire tech stack and collaborate effectively with teams to remediate issues at scale.
**Guard AI Data & Models:** Design and implement robust security controls for protecting critical data pipelines, sensitive model training environments, and customer-facing AI agents.
**Innovate AI Security Defenses:** Stay relentlessly ahead of emerging threats in the AI/ML security landscape. Research novel attack vectors specific to LLMs and generative AI, proactively building robust defenses against these unprecedented risks.

💡 What You Bring

**Proven AppSec Expertise:** 2+ years of hands-on experience in application security engineering, with a demonstrated track record of securing large-scale production systems. Bonus points if you've thrived in fast-growing startups or high-growth environments.
**Developer Empathy:** A deep understanding of the developer experience and engineering workflows for shipping features and products. You care deeply about reducing risk while simultaneously optimizing engineering velocity.
**Polyglot Coder:** Technical expertise in at least two programming languages (e.g., Python, Java, Go, JavaScript/TypeScript) and the ability to confidently read and review code across multiple languages, discerning both business logic and critical security implications.
**DevSecOps Mastery:** Profound knowledge of modern security tools and methodologies, including SAST/DAST solutions, vulnerability management platforms, advanced security testing frameworks, and best-in-class DevSecOps practices. You instinctively know which tools to wield and when automation surpasses manual review.
**Exceptional Communicator:** Outstanding communication skills that allow you to translate complex security concepts into clear, actionable recommendations for both highly technical and non-technical audiences. You can articulate "why" something matters and effectively motivate teams to action.
**Builder's Mindset:** A proactive, enabling mindset that consistently seeks opportunities to automate, scale, and empower, rather than create bottlenecks. You intrinsically understand that security is a business enabler, not a blocker.
**WRITER Values Alignment:** Strong alignment with WRITER's core values:

**Connect:** Building strong relationships and fostering collaboration across diverse teams.
**Challenge:** Pushing the boundaries of what's possible in AI security and beyond.
**Own:** Taking end-to-end responsibility and pride in the security of our platform.

🍩 Benefits & Perks (US Full-time employees)

Generous PTO, plus company holidays
Medical, dental, and vision coverage for you and your family
Paid parental leave for all parents (12 weeks)
Fertility and family planning support
Early-detection cancer testing through Galleri
Flexible spending account and dependent FSA options
Health savings account for eligible plans with company contribution
Annual work-life stipends for:

Wellness stipend for gym, massage/chiropractor, personal training, etc.
Learning and development stipend

Company-wide off-sites and team off-sites
Competitive compensation, company stock options and 401k

WRITER is an equal-opportunity employer and is committed to diversity. We don't make hiring or employment decisions based on race, color, religion, creed, gender, national origin, age, disability, veteran status, marital status, pregnancy, sex, gender expression or identity, sexual orientation, citizenship, or any other basis protected by applicable local, state or federal law. Under the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.
By submitting your application on the application page, you acknowledge and agree to WRITER's Global Candidate Privacy Notice.