Jobs in United Kingdom

Application Security Head in London

29 active opportunities · Updated October 2026

Explore current application security head jobs in London. Filter by work mode, employment type, experience, department, date posted and distance.

C
📍 London, London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

Who are we? Cohere is the leading security-first enterprise AI company. We build cutting-edge foundation AI models and end-to-end products that are designed to solve real-world business problems. We’re training and deploying frontier models for enterprises who are building AI systems. We believe that our work is instrumental to the widespread adoption of AI and we are looking for folks that want to be part of that. We obsess over what we build. Each one of us is responsible for contributing to increasing the capabilities of our models and the value they drive for our customers. Cohere is a team of researchers, engineers, designers, and more, who are all passionate about their craft. We are a global technology company headquartered in Toronto with key offices in London, New York City, San Francisco, Montreal, Paris, Berlin and Seoul. Join us! Please note that this is not a live role. We are grateful for your enthusiasm and interest in Cohere and encourage you to submit your resume for future consideration. Should a suitable position become available, we will review your application and reach out to discuss potential opportunities. Why this role? Design and implement novel research ideas, ship state of the art models to production, and maintain deep connections to academia. We have one of the highest ratio of compute to engineers in the world. We do not delineate strongly between engineering and research. Everyone will contribute to writing production code and conducting research depending on individual interest and organizational needs. We have all the compute, data, and talent available for you to do your best work. Please Note: We have offices in Toronto, London, Paris, San Francisco and New York but also embrace being remote-friendly! There are no restrictions on where you can be located for this role. As a Member of Technical Staff, you will: Design, build and scale AI systems for serving our users. Research, implement, and experiment with ideas on our supercompu

PythonGitRestAI
C
📍 London, London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

Who are we? Cohere is the leading security-first enterprise AI company. We build cutting-edge foundation AI models and end-to-end products that are designed to solve real-world business problems. We’re training and deploying frontier models for enterprises who are building AI systems. We believe that our work is instrumental to the widespread adoption of AI and we are looking for folks that want to be part of that. We obsess over what we build. Each one of us is responsible for contributing to increasing the capabilities of our models and the value they drive for our customers. Cohere is a team of researchers, engineers, designers, and more, who are all passionate about their craft. We are a global technology company headquartered in Toronto with key offices in London, New York City, San Francisco, Montreal, Paris, Berlin and Seoul. Join us! Why This Role? There's so much we can tell you about this role and why we're excited about it, but to keep it brief, here are the top things you need to know. We're excited to receive your application and talk to you soon! TL:DR: We're hiring an HR Business Partner to work with our Modelling organization, supporting Research and Engineering through an extraordinary phase of growth. A role that matters. HRBPs are central to our People model - trusted by leaders, brought into important organizational challenges, and expected to have a point of view. A front-row seat to AI. Work alongside exceptional researchers, engineers, and leaders at the forefront of AI - some of the most talented and in-demand people in the industry. A chance to build. We're building the foundations of our People function at scale, with plenty of white space and latitude to shape how we work rather than inherit established playbooks. Real ownership, with a built-in partner. You'll own relationships and priorities while working in an HRBP pod - giving you someone to bounce ideas off, share the load when needed, and provide seamless cover when you're away. An e

GitAIGoRust
C
📍 London, London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

Who are we? Cohere is the leading security-first enterprise AI company. We build cutting-edge foundation AI models and end-to-end products that are designed to solve real-world business problems. We’re training and deploying frontier models for enterprises who are building AI systems. We believe that our work is instrumental to the widespread adoption of AI and we are looking for folks that want to be part of that. We obsess over what we build. Each one of us is responsible for contributing to increasing the capabilities of our models and the value they drive for our customers. Cohere is a team of researchers, engineers, designers, and more, who are all passionate about their craft. We are a global technology company headquartered in Toronto with key offices in London, New York City, San Francisco, Montreal, Paris, Berlin and Seoul. Join us! Why this role? North is Cohere's cutting-edge AI workspace platform, designed to revolutionize the way enterprises utilize AI. It offers a secure and customizable environment, allowing companies to deploy AI while maintaining control over sensitive data. North integrates seamlessly with existing workflows, providing a trusted platform that connects AI agents with workplace tools and applications. The Agents & Automations team builds the platform inside North that lets customers create AI-powered workflows. Some of these workflows are structured automations, such as routing requests, keeping systems up-to-date, or triggering approvals. Others are more flexible agents that can gather context, use tools, make decisions, and take action across enterprise systems. As an engineer on this team, you will help build the core platform that makes this possible: the workflow builder, execution engine, integrations, debugging tools, observability, evaluation systems, and feedback loops that help customers understand and improve what they deploy. This is broad product engineering work across frontend, backend, and AI-powered systems. The

TypeScriptPythonReactKubernetes
C
📍 London, London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

Who are we? Cohere is the leading security-first enterprise AI company. We build cutting-edge foundation AI models and end-to-end products that are designed to solve real-world business problems. We’re training and deploying frontier models for enterprises who are building AI systems. We believe that our work is instrumental to the widespread adoption of AI and we are looking for folks that want to be part of that. We obsess over what we build. Each one of us is responsible for contributing to increasing the capabilities of our models and the value they drive for our customers. Cohere is a team of researchers, engineers, designers, and more, who are all passionate about their craft. We are a global technology company headquartered in Toronto with key offices in London, New York City, San Francisco, Montreal, Paris, Berlin and Seoul. Join us! Why this role? North is Cohere's cutting-edge AI workspace platform, designed to revolutionize the way enterprises utilize AI. It offers a secure and customizable environment, allowing companies to deploy AI while maintaining control over sensitive data. North integrates seamlessly with existing workflows, providing a trusted platform that connects AI agents with workplace tools and applications. The Agents & Automations team builds the platform inside North that lets customers create AI-powered workflows. Some of these workflows are structured automations, such as routing requests, keeping systems up-to-date, or triggering approvals. Others are more flexible agents that can gather context, use tools, make decisions, and take action across enterprise systems. As an engineer on this team, you will help build the core platform that makes this possible: the workflow builder, execution engine, integrations, debugging tools, observability, evaluation systems, and feedback loops that help customers understand and improve what they deploy. This is broad product engineering work across frontend, backend, and AI-powered systems. The

TypeScriptPythonReactKubernetes
C
📍 London, London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

Who are we? Cohere is the leading security-first enterprise AI company. We build cutting-edge foundation AI models and end-to-end products that are designed to solve real-world business problems. We’re training and deploying frontier models for enterprises who are building AI systems. We believe that our work is instrumental to the widespread adoption of AI and we are looking for folks that want to be part of that. We obsess over what we build. Each one of us is responsible for contributing to increasing the capabilities of our models and the value they drive for our customers. Cohere is a team of researchers, engineers, designers, and more, who are all passionate about their craft. We are a global technology company headquartered in Toronto with key offices in London, New York City, San Francisco, Montreal, Paris, Berlin and Seoul. Join us! Why This Role? North is Cohere’s AI workspace platform for enterprises: a secure, customizable environment where companies can use AI across their real workflows while maintaining control over sensitive data. North connects AI agents with workplace tools, applications, and business context, helping users delegate complex work, build automations, inspect outputs, and collaborate with AI in production environments. As North becomes more capable, one of the most important questions is also one of the hardest: how do we know whether the model is actually getting better for the workflows customers care about? This role is about being the voice of North inside modelling. You will build the evaluation systems, feedback loops, and applied modelling workflows that make sure model progress translates into better product outcomes for North users. You will work closely with North product teams, customer-facing teams, and modelling teams to define what “good” means across the product surface, turn real usage and product direction into high-quality evals, and use those evals to guide model selection, patches, and regular model updates. This i

W
📍 London, England, United Kingdom· Full-time· Remote
✓ High-confidence listingCompany trend +37.5%
Quick readStrong listing-quality and freshness signals

🚀 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

JavaScriptTypeScriptPythonJava
W
📍 London, England, United Kingdom· Full-time· Remote
✓ High-confidence listingCompany trend +37.5%
Quick readStrong listing-quality and freshness signals

🚀 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

JavaScriptTypeScriptPythonJava
W
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing
Quick readStrong listing-quality and freshness signals

WPP is the trusted growth partner for the world’s leading brands. We unite cutting-edge media intelligence and data solutions, world-class creativity, next-generation production, transformative enterprise solutions and expert strategic counsel in a single company – powered by exceptional talent and our agentic marketing platform, WPP Open, to help our clients navigate change, capture opportunity and deliver transformational growth. We work with the world's most valuable brands and have global reach across 100+ markets, with deep local expertise. Our people are the key to our success. We're committed to fostering a culture of creativity, belonging and continuous learning, attracting and developing the brightest talent, and providing exciting career opportunities that help our people grow. For more information, visit WPP.com. Why we're hiring: We're looking for an Application & Development Security Lead to help shape and strengthen secure software development governance across one of the world's largest technology and creative ecosystems. Working within WPP's Digital Security & Risk Management team, you'll partner with engineering, product and platform teams to govern secure-by-design ways of working, improve software security governance, and provide oversight across modern development environments. This role isn't about writing code day-to-day. Instead, you'll influence governance of how secure software is built, deployed and maintained across cloud-native platforms, APIs, AI-enabled applications and global engineering teams. This is an opportunity to influence software security governance at global scale, helping shape how security supports innovation across one of the world's largest and most diverse technology environments. You'll work alongside talented security and engineering professionals while helping build secure, resilient products and platforms for the future. What you'll be doing: Define an

AWSAzureCI/CDGit
O
📍 London, Greater London, United Kingdom· Full-time
✓ Quality checkedCompany trend -100%

About the Team The Applications Engineering team works across research, engineering, product, and design to bring OpenAI’s technology to consumers and businesses. You’ll join the team responsible for running the core infrastructure that supports products like ChatGPT and the API. The systems we support include our kubernetes clusters, infrastructure deployment, our networking stack, cloud abstractions, and more. We seek to learn from deployment and distribute the benefits of AI, while ensuring that this powerful tool is used responsibly and safely. Safety is more important to us than unfettered growth. About the Role The cloud infrastructure team builds and maintains infrastructure abstractions allowing OpenAI to ship products quickly and scalably. In this role, you will: Design and build the development and production platforms that power our products, enabling reliability and security at scale Ensure our infrastructure can scale to the next order of magnitude Help create a diverse, equitable, and inclusive culture that makes all feel welcome while enabling radical candor and the challenging of group think Like all other teams, we are responsible for the reliability of the systems we build. This includes an on-call rotation to respond to critical incidents as needed. You might thrive in this role if you: Have 5+ years building core infrastructure Have experience operating orchestration systems such as Kubernetes at scale Have experience building abstractions over cloud platforms Take pride in building and operating scalable, reliable, secure systems Are comfortable with ambiguity and rapid change About OpenAI OpenAI is an AI research and deployment company dedicated to ensuring that general-purpose artificial intelligence benefits all of humanity. We push the boundaries of the capabilities of AI systems and seek to safely deploy them to the world through our products. AI is an extremely powerful tool that must be created with safety and human needs at its core, and

AWSKubernetesRestAI
W
📍 London, England, United Kingdom· Full-time· Remote
✓ High-confidence listingCompany trend +37.5%
Quick readStrong listing-quality and freshness signals

🚀 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 We’re seeking a highly skilled fullstack software engineer to join our engineering team building advanced AI-driven agent systems that execute autonomous workflows, orchestrate multi-step tasks, and extend human capacity across enterprise applications. In this role, you’ll play a key part in designing, building, and scaling next-generation AI agents that integrate with enterprise data and services to solve real-world problems. You will collaborate with cross-functional teams to turn complex agent concepts into production-ready systems. 🦸🏻‍♀️ What you'll do Design, implement, and maintain scalable, secure agent-driven services and systems that autonomously accomplish tasks using modern AI frameworks. Develop and enhance robust infrastructure and high-throughput APIs, focusing on core agent capabilities such as memory, communication channels, skills, intelligent decision logic, security and workflow management. Integrate agent capabilities with backend services

TypeScriptPythonReactAWS
S
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing

£107K – £262K/yr

Quick readStrong listing-quality and freshness signals

SpaceXAI’s mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. Our team is small, highly motivated, and focused on engineering excellence. This organization is for individuals who appreciate challenging themselves and thrive on curiosity. We operate with a flat organizational structure. All employees are expected to be hands-on and to contribute directly to the company’s mission. Leadership is given to those who show initiative and consistently deliver excellence. Work ethic and strong prioritization skills are important. All employees are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates. ABOUT THE ROLE: We’re seeking an exceptional iOS engineer to join a small, high-impact team dedicated to creating the world’s most valuable AI application, judged by the impact it delivers to users. You’ll shape cutting-edge mobile experiences, blending technical mastery with product brilliance. RESPONSIBILITIES: Dream up and craft delightful, intuitive user experiences that redefine how people interact with AI on mobile. Obsess over every pixel, animation, and interaction, ensuring the experience feels magical and seamless. Build blazing-fast, highly performant systems where every millisecond counts. Drive technical and product decisions, collaborating with AI researchers and engineers to deploy state-of-the-art models globally. BASIC QUALIFICATIONS: Expert in Swift, with deep knowledge of SwiftUI and UIKit. Proficient in performance optimization—memory, CPU, GPU—using low-level tools to deliver blazing-fast systems. Experienced in designing and shipping intuitive, pixel-perfect mobile UIs that redefine how users interact with AI. Skilled in concurrency and reactive programming (Combine) for responsive, real-time apps. Built high-throughput integrations with APIs (REST, gRPC) or AI model outputs, ensuring seamless data

ReactRestAISwift
S
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing

£107K – £262K/yr

Quick readStrong listing-quality and freshness signals

SpaceXAI’s mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. Our team is small, highly motivated, and focused on engineering excellence. This organization is for individuals who appreciate challenging themselves and thrive on curiosity. We operate with a flat organizational structure. All employees are expected to be hands-on and to contribute directly to the company’s mission. Leadership is given to those who show initiative and consistently deliver excellence. Work ethic and strong prioritization skills are important. All employees are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates. ABOUT THE ROLE: We're seeking an exceptional Android engineer to join a small, high-impact team dedicated to creating the world's most valuable AI application, judged by the impact it delivers to users. You'll shape cutting-edge mobile experiences, blending technical mastery with a keen product sense to deliver brilliance that resonates with users. You will work on the most critical product or technical challenge at any given time. BASIC QUALIFICATIONS: Proficient in Kotlin, Jetpack Compose and reactive programming. Has a strong product sense and high craft bar. Builds intuitive and delightful user experiences. Experienced in architecting modern large production apps while embodying technical excellence. Strong sense of ownership and agency. Able to put on multiple hats and take responsibility for large areas. Able to optimize for performance, stability and reliability. PREFERRED SKILLS AND EXPERIENCE: A proven track record of shipping standout apps or features that demonstrate both technical excellence and exceptional product intuition. Deep expertise in the Android ecosystem and related development tools (Android Studio, Gradle, etc.). Rust for working with our backend components. COMPENSATION AND BENEFITS: £107,000 - £262,0

ReactAIKotlinRust
FB
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing
Quick readStrong listing-quality and freshness signals

Location : Come and join us in London! Freenow by Lyft empowers smarter mobility decisions helping people to move freely and cities to thrive. One of our core goals for 2026 is the complete digitalization of the European taxi market. We work with taxi companies to provide them with our advanced dispatch and fleet management software completely free of charge. This enables them to significantly reduce operating costs, successfully differentiate themselves from major ride-hailing providers, and manage a profitable, sustainable business. To support this, we are looking for a Sales Manager who will become the face of this initiative. We look forward to your application and can't wait to have you on board for this journey! YOUR DAILY ADVENTURES WILL INCLUDE: Prospect, engage, travel and pitch our Dispatch tool to SME taxi companies in the UK. You are the driving force behind converting traditional vehicle fleets into modern, connected Freenow by Lyft partners. Guide entrepreneurs, fleet owners, and senior dispatchers through the fear of operational change. Act as the voice of our partners. You will gather on-the-ground feedback about our software and collaborate directly with our Product and Strategy teams to help "co-build" the ultimate solution. TO BE SUCCESSFUL IN THIS ROLE: 3-5 years of professional experience in areas such as B2B business development, sales, or account management. Experience in mobility, logistics, or selling SaaS solutions to SMEs is especially valued. Proven track record of managing a B2B pipeline and handling objections. You understand that even when a product is free, you still have to expertly "sell" the time, effort, and operational shift required to adopt it. Strong communication skills with the ability to build trust and long-term relationships. The ability to deeply understand a partner's business operations at a process level. You are skilled at guiding new partners step by step through the change process and ensuring they smoothly a

GitAIGoRust
FB
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing
Quick readStrong listing-quality and freshness signals

Location : Come and join us in London! Freenow by Lyft empowers smarter mobility decisions helping people to move freely and cities to thrive. One of our core goals for 2026 is the complete digitalization of the European taxi market. We work with taxi companies to provide them with our advanced dispatch and fleet management software completely free of charge. This enables them to significantly reduce operating costs, successfully differentiate themselves from major ride-hailing providers, and manage a profitable, sustainable business. To support this, we are looking for a Sales Manager who will become the face of this initiative. We look forward to your application and can't wait to have you on board for this journey! YOUR DAILY ADVENTURES WILL INCLUDE: Prospect, engage, travel and pitch our Dispatch tool to SME taxi companies in the UK. You are the driving force behind converting traditional vehicle fleets into modern, connected Freenow by Lyft partners. Guide entrepreneurs, fleet owners, and senior dispatchers through the fear of operational change. Act as the voice of our partners. You will gather on-the-ground feedback about our software and collaborate directly with our Product and Strategy teams to help "co-build" the ultimate solution. TO BE SUCCESSFUL IN THIS ROLE: 3-5 years of professional experience in areas such as B2B business development, sales, or account management. Experience in mobility, logistics, or selling SaaS solutions to SMEs is especially valued. Proven track record of managing a B2B pipeline and handling objections. You understand that even when a product is free, you still have to expertly "sell" the time, effort, and operational shift required to adopt it. Strong communication skills with the ability to build trust and long-term relationships. The ability to deeply understand a partner's business operations at a process level. You are skilled at guiding new partners step by step through the change process and ensuring they smoothly a

GitAIGoRust
W
📍 London, England, United Kingdom· Full-time
✓ High-confidence listing
Quick readStrong listing-quality and freshness signals

WPP is the trusted growth partner for the world’s leading brands. We unite cutting-edge media intelligence and data solutions, world-class creativity, next-generation production, transformative enterprise solutions and expert strategic counsel in a single company – powered by exceptional talent and our agentic marketing platform, WPP Open, to help our clients navigate change, capture opportunity and deliver transformational growth. We work with the world's most valuable brands and have global reach across 100+ markets, with deep local expertise. Our people are the key to our success. We're committed to fostering a culture of creativity, belonging and continuous learning, attracting and developing the brightest talent, and providing exciting career opportunities that help our people grow. For more information, visit WPP.com. Why we're hiring: WPP Media, as part of WPP ET, is undergoing a significant transformation, modernising our ways of working, adopting cloud-native architectures, and prioritising AI and data-driven insights. This role is crucial for infusing AI-first thinking at every level. You will bridge the gap between high-level business strategy and hands-on technological exploration, acting as a catalyst for innovation. We need someone who can work closely with our teams to discover, design, and help deliver a truly reimagined future powered by AI, ensuring solutions align with our enterprise architectural principles and standards. Are you a hands-on technologist with a solid understanding of the media or advertising business, eager to explore and apply cutting-edge AI? This isn't a traditional Enterprise Architect role focused purely on mapping and integration. Instead, we're seeking an aspiring architect who thrives on discovery and practical application. You will be instrumental in exploring how emerging technologies, especially agentic AI, can fundamentally reimagine our business operati

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