---
title: 'Security engineer, application security (UK) at WRITER'
canonical: 'https://feeny.ai/job/security-engineer-application-security-uk-writer-london-3fgyyv2916fk'
type: 'job'
last_seen: '2026-09-09'
---

# Security engineer, application security (UK) at WRITER

- **Company:** WRITER
- **Location:** London, United Kingdom
- **Employment:** full-time
- **Work type:** hybrid
- **Posted:** 2026-09-04
- **Last confirmed live:** 2026-09-09
- **Apply:** https://jobs.ashbyhq.com/writer/60cc89b9-b582-49d2-b9e8-b83af6094da5

## Job description

## 🚀 ABOUT WRITER

WRITER is where the world's leading enterprises orchestrate AI-powered work. Our vision is to expand human capacity through superintelligence. And we're proving it's possible – through powerful, trustworthy AI that unites IT and business teams together to unlock enterprise-wide transformation. With WRITER's end-to-end platform, hundreds of companies like Mars, Marriott, Uber, and Vanguard are building and deploying AI agents that are grounded in their company's data and fueled by WRITER's enterprise-grade 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 leader in enterprise generative AI.

Founded in 2020 with office hubs in San Francisco, New York City, Seattle, Austin, Chicago, and London, our team thinks big and moves fast, and we're looking for smart, hardworking builders and scalers to join us on our journey to create a better future of work with AI.

## 📐 ABOUT THE ROLE

This is where security meets innovation at enterprise scale. As a security engineer, applications at WRITER, you'll be building the security foundations that protect the AI systems powering some of the world's most recognizable brands. You'll work at the intersection of application security, AI infrastructure, and developer enablement—partnering with engineering teams to embed security into every line of code while ensuring our platform remains both powerful and trustworthy.

The opportunity is massive: you'll help define how enterprise AI applications are secured, from threat modeling our LLM architectures to building automated security controls that scale across our growing platform. This isn't about saying "no"—it's about finding creative ways to say "yes, and here's how we do it securely." You'll tackle challenges that most security engineers never encounter: securing AI agents, protecting training data pipelines, and designing controls for systems that didn't exist a few years ago.

This role is hybrid from our London office, reporting to the head of security engineering.

## 🦸🏻‍♀️ WHAT YOU'LL DO

- Build security into the DNA of our AI platform by conducting threat modeling sessions with product teams, designing secure architectures for new features, and ensuring security considerations shape product decisions from day one—not after the fact
- Own and evolve our application security program including establish and maintain SAST/DAST scanning in CI/CD pipelines, conducting security code reviews for critical changes, and building automation that catches vulnerabilities before they reach production
- 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
- Design and recommend security features and products that help secure customer environments. You are the advocate and the vision for how we protect and secure customers..
- Integrate and leverage AI agents to help increase velocity for the security team and the overarching engineering org to ensure that we are proactive in minimizing risk while we build products
- Lead security assessments and penetration testing of WRITER's applications, AI services, and APIs, identifying vulnerabilities across our tech stack and working collaboratively with teams to remediate issues at scale
- Design and implement security controls for protecting data pipelines, model training environments, and customer-facing AI agents
- Stay ahead of emerging threats in the AI/ML security landscape, researching attack vectors specific to LLMs and generative AI, and proactively building defenses against novel risks

## ⭐️ WHAT YOU NEED

- 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
- Understanding of developer experience and developer workflows for shipping features and products. You care deeply about reducing risk while considering velocity of engineers.
- 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
- 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
- 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
- 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
- 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)

🍩 Benefits & perks (UK full-time employees):

- Generous PTO, plus company holidays
- Comprehensive medical and dental insurance
- Paid parental leave for all parents (16 weeks)
- Fertility and family planning support
- Early-detection cancer testing through Galleri https://www.galleri.com/partner/writer
- Competitive pension scheme and 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 and company stock options

## About WRITER

## Company Overview
- **One-liner**: WRITER provides an enterprise AI platform that enables organizations to build, activate, and supervise AI agents grounded in company data and powered by its own family of large language models (LLMs).
- **Entity Type**: Private (Series C; $326M total funding)
- **Headquarters**: San Francisco, California, United States
- **Founded**: 2020
- **Founders**: May Habib (CEO) & Waseem AlShikh (CTO)

## Core Business
- **Primary Industry**: Enterprise AI / Generative AI Software Development
- **Target Customers**: B2B; Large enterprises in regulated industries (e.g., financial services, healthcare, professional services). Named customers include Accenture, Mars, Marriott, Uber, and Vanguard.
- **Mission Statement**: To expand human capacity through superintelligence by building trustworthy AI that unites IT and business teams for enterprise-wide transformation.

## Products & Services
- **WRITER Platform**: An end-to-end platform for building, deploying, and monitoring AI agents that are grounded in enterprise data and governed by IT controls. Includes an "AI Studio" for custom agent creation.
- **WRITER Agent**: A delegation-based agent that executes complex, multi-step workflows from natural language instructions (e.g., drafting reports, conducting research, generating compliant content).
- **Palmyra Family of LLMs**: WRITER’s own suite of purpose-built LLMs, designed for transparency, reliability, and control in regulated environments.
- **Security & Compliance Integrations**: Pre-built integrations with enterprise security, identity, and observability stacks (e.g., SSO, audit logs, role-based access controls) to meet compliance standards.

## Market Standing
- **Valuation/Market Cap**: Not publicly disclosed (total funding of $326M).
- **Key Metric**: Annual recurring revenue (ARR) estimated at $26M (source: LinkedIn company profile).
- **Notable Investors**: Premji Invest, Radical Ventures, ICONIQ Growth, Insight Partners, Balderton Capital, B Capital, Salesforce Ventures, Adobe Ventures, Citi Ventures, IBM Ventures.
- **Growth Signals**: Headcount of ~727 employees (+33.1% YoY); operates in 42 countries; LinkedIn followers grew +35.7% YoY to ~88k; expanding office footprint with hubs in San Francisco, New York, London, Chicago, and Austin.

## Competitive Advantages
- **Five-year track record of in-house LLM R&D**: Co-founders have been building AI for enterprise since 2013 (first company focused on machine translation). WRITER controls its own model stack, not just a wrapper on third-party APIs.
- **Enterprise-first DNA**: Platform is built from the ground up for governance, compliance, and IT integration — a key differentiator in regulated industries.
- **Purpose-built for agentic workflows**: Unlike generic chatbot platforms, WRITER focuses on autonomous, multi-step task execution with deep domain context.
- **Strong partner ecosystem**: Backed by a consortium of strategic investors including Salesforce, Adobe, Citi, and IBM, signaling deep enterprise channel potential.

## Strategic Focus
- **Agentic AI for the enterprise**: Moving beyond simple prompting to autonomous agents that can be delegated complex tasks.
- **Deepening IT and security integrations**: Making it easy for security and compliance teams to approve and deploy AI at scale.
- **Expanding AI research**: Continuing to invest in the Palmyra family of LLMs to maintain frontier capabilities.
- **Global expansion**: Growing presence across North America and Europe (offices in SF, NY, London, Chicago, Austin).

## Why Work Here
- **Hybrid culture**: The company is built around a mix of in-office collaboration and remote work. Offices are in San Francisco, New York, and London (plus Chicago and Austin).
- **Ownership mindset**: All employees receive company stock options, plus a 401k plan with employer contributions.
- **Growth opportunities**: "Expect to quickly improve your skills and expand your responsibilities" — learning and development stipend and generous PTO are provided.
- **Cutting-edge technical challenges**: Teams build advanced AI technology from scratch, solving problems few other companies tackle.
- **Comprehensive benefits**: Employer-covered medical, dental, and vision plans; life insurance; FSA; competitive parental leave; family-friendly policies.
- **Strong values-driven culture**: Emphasizes active listening, high standards, long-term thinking, and diverse perspectives.
- **Active hiring**: Multiple open roles across engineering, product, sales, and customer success (see careers page).

## Sources
1. [writer.com/about](https://writer.com/company/about/)
2. [writer.com](https://writer.com/)
3. [writer.com/careers](https://writer.com/company/careers/)
4. [LinkedIn Company Profile](https://www.linkedin.com/company/getwriter)
5. [Ashby Careers Page](https://jobs.ashbyhq.com/writer)

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