🚀 About WRITER
WRITER is at the vanguard of enterprise AI, orchestrating intelligent solutions that expand human capacity through superintelligence. We empower the world's leading organizations – including Mars, Marriott, Uber, and Vanguard – to build and deploy powerful, trustworthy AI agents, grounded in their data and fueled by our enterprise-grade LLMs. Valued at $1.9B and backed by industry giants like Premji Invest, Radical Ventures, and ICONIQ Growth, we are rapidly defining the future of generative AI.
Founded in 2020 with dynamic hubs in San Francisco, New York City, Austin, Chicago, and London, our team moves fast and thinks big. We're seeking smart, hardworking builders and scalers to join us in creating a better, more secure future of work with AI.
📐 About the Role: Security Engineer, Applications
This is where your security expertise meets the cutting edge of AI innovation at an unprecedented scale. As a Security Engineer, Applications at WRITER, you won't just protect systems; you'll forge the very security foundations that safeguard the AI powering some of the world's most recognizable brands. You'll operate at the critical intersection of application security, advanced AI infrastructure, and developer enablement, embedding robust security into every line of code while ensuring our platform remains both powerful and unimpeachably trustworthy.
The opportunity ahead is immense and unparalleled: you will actively define how enterprise AI applications are secured. This includes pioneering threat modeling for our complex LLM architectures and engineering automated security controls that scale seamlessly across our rapidly expanding platform. This isn't a role about restrictive "no's"; it's about ingeniously finding ways to say, "Yes, and here's how we achieve it securely." You'll tackle novel challenges few security engineers ever encounter: securing intelligent AI agents, protecting sensitive training data pipelines, and designing controls for systems that were unimaginable just a few years ago.
This hybrid role is based out of our London office, reporting directly to the Head of Security Engineering.
🦸🏻♀️ What You'll Do
Architect security from the ground up, embedding it deeply within our AI platform by leading threat modeling sessions with product teams, designing secure architectures for new features, and ensuring security considerations shape product decisions from day one.
Drive the evolution and ownership of our application security program, including establishing and maintaining advanced SAST/DAST scanning within CI/CD pipelines, conducting thorough security code reviews for critical changes, and building automation that proactively catches vulnerabilities before they ever reach production.
Collaborate strategically with engineering teams to establish and champion secure coding standards, developing reusable security patterns and libraries that empower developers to build securely by default.
Design and recommend innovative security features and products that enhance the protection of customer environments. You will be the visionary advocate for how we secure and protect our customers.
Integrate and leverage AI agents to accelerate the security team's velocity and the broader engineering organization, ensuring we are proactive in minimizing risk as we build ground-breaking products.
Lead comprehensive security assessments and penetration testing of WRITER's applications, AI services, and APIs, meticulously identifying vulnerabilities across our entire tech stack and collaborating effectively with teams to remediate issues at scale.
Engineer and implement robust security controls specifically designed for protecting critical data pipelines, sensitive model training environments, and customer-facing AI agents.
Stay at the forefront of emerging threats in the AI/ML security landscape, conducting deep research into attack vectors unique to LLMs and generative AI, and proactively building cutting-edge defenses against novel risks.
⭐️ What You'll Bring
4+ years of hands-on experience in application security engineering, with a proven track record of securing large-scale production systems. Experience in fast-growing startups or high-growth environments is a significant advantage.
A keen understanding of developer experience and workflows for shipping features and products. You care deeply about reducing risk while empowering engineering velocity.
Technical mastery in at least two programming languages (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.
In-depth knowledge of security tools and methodologies, including SAST/DAST solutions, vulnerability management platforms, security testing frameworks, and advanced DevSecOps practices. You understand which tools to leverage and when automation outperforms manual review.
Exceptional communication skills that enable 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.
A true builder's mindset, consistently seeking opportunities to automate, scale, and empower rather than create bottlenecks. You intrinsically understand that security enables the business, it doesn't block it.
Alignment with WRITER's core 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).
🍩 Benefits & Perks (UK full-time employees): Generous PTO, plus company holidays Wellness stipend for gym, massage/chiropractor, personal training, etc. Company-wide off-sites and team off-sites
Comprehensive medical and dental insurance
Paid parental leave for all parents (16 weeks)
Fertility and family planning support
Early-detection cancer testing through Galleri
Competitive pension scheme and company contribution
Annual work-life stipends for:
Learning and development stipend
Competitive compensation and company stock options