--- title: 'Forward Deployed Product Engineer at Cosine' canonical: 'https://feeny.ai/job/forward-deployed-product-engineer-cosine-london-ftwnedhnsvwb' type: 'job' last_seen: '2026-09-14' --- # Forward Deployed Product Engineer at Cosine - **Company:** Cosine - **Location:** London, United Kingdom - **Compensation:** £100k–£120k - **Employment:** full-time - **Work type:** onsite - **Posted:** 2026-05-14 - **Last confirmed live:** 2026-09-14 - **Apply:** https://jobs.ashbyhq.com/cosine/1c4aef01-61ee-40ba-b919-f77a244b3847 ## Job description Job Title: Forward Deployed Product Engineer Location: London; full in-office working as default Start date: ASAP Reports to: Head of Engineering Compensation: £100,000 - £120,000 + EQUITY ___________________________________________________________________________ Cosine at a glance Cosine is the UK's frontier AI lab for autonomous software engineering — not another coding assistant, but our own models, agent stack, eval harnesses, and product layer. We build our agent tooling entirely in-house and post-train open-source models to deliver reliable, enterprise-grade coding performance in security-critical settings. Our offerings can be used as SaaS, deployed on VPC, on-prem or fully air-gapped. Through this flexability, we are able to service large-scale, highly regulated enterprises and industries including defence, financial service and healthcare. We’re backed by YC and were recently selected for the UK’s sovereign AI programme. The company is at a rare stage: deep technical work, real enterprise pull, and a chance to shape how AI is deployed inside defence, banking, government, and other high-trust environments. This role is based in our Hoxton office, five days a week, because close collaboration, fast feedback, and shared context matter for the problems we’re solving. ___________________________________________________________________________ ## The role A Forward Deployed Product Engineer at Cosine works directly with customers and closely across research, engineering, infrastructure, product, and design to turn advanced AI capabilities into intuitive, reliable tools for developers, and deploy them successfully in complex customer environments. You will be responsible for building and evolving Cosine’s user-facing product surfaces, including dedicated apps and web applications that expose the power of our models through well-designed workflows and interfaces. Your work sits at the intersection of product, platform, and research, translating emerging model capabilities into concrete experiences developers can use every day. You will work directly with customers to assess their needs, understand their workflows and technical constraints, and design and help implement solutions that meet those needs. You will take ownership of deploying, integrating, and troubleshooting Cosine in complex, security-critical environments, bringing what you learn back into the core product. Hands-on full-stack product development is a central part of the role. We focus on rapid product iteration without compromising quality. This means building systems that are performant, observable, and robust, while remaining flexible enough to evolve alongside fast-moving research and user needs. You will help define how developers interact with Cosine, from first use through advanced, production-grade workflows. ___________________________________________________________________________ ## Your Mission Push the boundaries of what an autonomous agentic AI engineer can do by building scalable, high-quality web application interfaces and integrations that expose the power of our models in intuitive, reliable ways, and working directly with customers to deploy solutions that meet their needs in complex environments. ## Responsibilities - Build end-user products (command line interfaces, web applications and platform capabilities) that integrate with the Cosine platform APIs - Work directly with customers to assess their needs, workflows, infrastructure, and security constraints, and translate these into solution designs and implementation plans - Own the technical delivery of customer solutions, from deployment and integration with existing systems through troubleshooting and reliable production use - Diagnose and resolve issues across application code, APIs, infrastructure, and customer environments, collaborating with customer teams and internal specialists - Feed customer requirements and deployment learnings back into reusable product features and integrations - Enable developers to use advanced language models to augment their workflows and problem-solving capabilities - Collaborate closely research to explore and validate new product experiences and capabilities - Translate emerging model capabilities into concrete, user-facing features - Maintain a high bar for performance, reliability, and usability across platforms - Be opinionated about and bring your own ideas to the table, we’re building for engineers, as an engineer you have a say in what you want to use. ___________________________________________________________________________ ## Skills & Experience Forward Deployed Engineering & Customer Delivery - Prior experience as a Forward Deployed Engineer is required - Must hold current security clearance - Experience working directly with customers to assess their needs and translate business requirements, technical constraints, and security requirements into practical solution designs - Hands-on experience deploying, integrating, and troubleshooting software in complex customer environments - Ability to own technical delivery from discovery and solution design through implementation and production support - Strong communication skills, with the ability to work effectively with technical and non-technical customer stakeholders Frontend & Application Development - Experience building reactive, highly interactive applications (React, Svelte, Vue) - Experience with cli application development or local software development is a plus Backend & Systems - Experience with backend development - Experience designing and consuming REST APIs Developer Experience - Experience working with developer tooling - Familiarity with CI/CD pipelines - Experience with containerization Programming Languages - Strong experience with TypeScript and modern frontend frameworks - Knowledge of Node.js, Python, and Go is a plus Tooling & Infrastructure - Git, Docker, Webpack, npm, Kubernetes, GCP - Monitoring and alerting tools (e.g. Grafana, Datadog) - Feature flagging systems ___________________________________________________________________________ You Might Thrive in This Role If You: - Have 5+ years of experience building production-grade software. - Have shipped and maintained complex frontend or full-stack applications used by technical users. - Are comfortable building highly interactive web or IDE-based experiences using modern frameworks (e.g. React, TypeScript). - Have experience designing and consuming APIs, and understand how frontend and backend systems evolve together. - Enjoy working directly with customers, understanding their needs, and taking responsibility for making solutions work in their environments. - Are comfortable moving between hands-on full-stack product development, customer-facing solution design, and deployment troubleshooting. - Enjoy working close to the product surface, translating ambiguous ideas and model capabilities into intuitive developer workflows. - Care deeply about developer experience, performance, and reliability - not just functionality. - Are comfortable iterating quickly, running experiments, and refining products based on real user feedback. - Can operate effectively in a fast-moving environment with evolving priorities and incomplete information. ___________________________________________________________________________ Cosine is an equal opportunity employer. We value diverse backgrounds, perspectives, and ways of thinking, and we’re committed to creating an inclusive and respectful workplace. We encourage applications from anyone who meets the role requirements, even if you don’t meet every single qualification. If you need reasonable adjustments at any stage of the hiring process, we’re happy to discuss them. ___________________________________________________________________________ ## Compensation, Benefits & Ways of Working We’re an in-office team, five days a week, by design. We believe the work we’re doing benefits from being together, collaborating closely, and building shared context. What you can expect: - Competitive salary, benchmarked to the market - Equity / share options, so you share in the upside you help create - 30 days’ holiday + bank holidays - Genuine 9–5 working hours - we don’t expect late nights or weekend work - Work hard in the office, collaborate closely, and switch off properly - Dog-friendly office - bring your dog to work - Weekly team breakfast & lunch - Monthly socials - Pension - High-quality equipment to do your best work We care about focus, sustainability, and doing great work - not performative overwork. We value people who show up, contribute thoughtfully, collaborate well with their colleagues, and then go home. This role won’t suit everyone. But if you want structure, clarity, strong collaboration, and a team that takes both the work and work-life balance seriously, it’s a great place to be. ___________________________________________________________________________ Agency & Data Protection Notice To comply with UK GDPR and our internal data-protection and equal-opportunity obligations, we only accept candidate applications and agency submissions via our Applicant Tracking System (ATS). This ensures appropriate privacy notices, lawful processing, auditability, and consistent retention controls. Any CVs or candidate details received outside the ATS (including via email, Slack, or direct message) will be treated as unsolicited, will not be considered as part of the recruitment process, and will not give rise to any fee or payment obligation. ## About Cosine ## Company Overview - **One-liner**: Cosine is a sovereign AI frontier lab and developer of Lumen, a specialist coding model and fully agentic software engineering system that outperforms generalist models on real-world code tasks. - **Entity Type**: Private (Venture-backed) - **Headquarters**: London, United Kingdom - **Founded**: 2022 - **Founders**: Yang Li, Alistair Pullen, Sam Stenner ## Core Business - **Primary Industry**: Artificial Intelligence, Software Development - **Target Customers**: Enterprise, Defense, Finance, Government, Healthcare, and other high-security, high-trust environments (B2B) - **Mission**: Build sovereign AI engineering systems that serious teams can rely on in secure environments where reliability, privacy, and control matter most. ## Products & Services - **Lumen (Model Family)**: A specialist family of AI models trained exclusively on production-quality code. Outperforms generalist models (OpenAI, Anthropic, DeepSeek) on code benchmarks. Includes variants: - **Scout** (8B parameters): Fast, on-device, for in-repo context. - **Outpost**: Post-trained from Kimi K2.6, optimized for enterprise and niche languages (COBOL, Fortran, Verilog, Rust, complex SQL). - **Frontier**: Highest-performing model (coming soon), achieving 59.3% on internal Niche-Bench vs. GPT-5.4 (47.4%). - **Cosine Agent**: A fully agentic SWE that allows users to work on tickets asynchronously. Operates within a terminal-native interface, with multi-agent orchestration, MCP tool access, and a local-to-remote execution model. - **Cosine Cloud**: Fully managed public cloud offering for teams. - **Enterprise Deployment**: Managed single-tenant cloud and fully air-gapped on-premise deployments for maximum security. ## Market Standing - **Valuation**: Not disclosed - **Key Metric**: Annual Revenue of **$1.0M** (as of latest data); Total Funding of **$3.0M**. - **Funding History**: - Pre-Seed (Nov 2022): $500K, led by Y Combinator (W23 batch). - Seed (Aug 2024): $2.5M, led by UpHonest Capital and Soma Capital (6 investors). - Grant (Apr 2026): 1 investor. - **Notable Investors/Partners**: Y Combinator, UpHonest Capital, Soma Capital; Member of UK government’s £500M **Sovereign AI programme**; granted access to the **Isambard-AI** supercomputer. - **Growth Signals**: Headcount has grown **60.9% YoY** (to ~23 employees); has assembled a UK Sovereign AI coalition of defense, infrastructure, financial, and healthcare leaders. Models have topped public benchmarks for two consecutive years. ## Competitive Advantages - **Specialist-Over-Generalist Moat**: Lumen is a model trained exclusively on production code, not general text; this leads to significantly better results on code benchmarks (e.g., 59.3% on Niche-Bench vs. GPT-5.4’s 47.4%). - **Sovereign AI**: First company to train, own, and deploy a fully sovereign AI model entirely on UK soil. This is a critical differentiator for defense, national security, and critical infrastructure where foreign AI is legally off the table. - **Full-Stack In-House Build**: Owns the entire stack (models, agent infrastructure, evaluation, product surfaces, deployment) allowing deep integration and rapid iteration. - **Real-World Deployment**: Deployed in air-gapped, on-premise environments for security-conscious customers who cannot use cloud-based AI. ## Strategic Focus - **Sovereign AI Leadership**: Deepening its role as Britain’s national AI champion, working with the UK government on the £500M Sovereign AI programme. - **Enterprise & Government Sales**: Expanding into defense, finance, infrastructure, and healthcare with secure, private deployments. - **Pushing Agentic Boundaries**: Moving beyond chat and autocomplete to build AI agents that plan, reason, write, test, and ship code inside real development workflows. - **Technical Scaling**: Building larger, more capable Frontier models and improving the training infrastructure (synthetic data, RL, reward functions). ## Why Work Here - **Pioneering Work**: Build the future of autonomous software engineering at a company that leads the field in code-focused AI. - **High Ownership**: Engineers own the full stack; work directly influences what the product becomes. - **Culture**: Emphasizes direct communication, deep ownership, customer obsession, and “doing the hard thing.” Avoids performative overwork (standard 9-5, no regular late work or weekends). - **In-Office by Design**: Primarily in-office (London) for close collaboration and fast feedback. - **Benefits**: Competitive salaries, share options, pension (NEST), cycle-to-work scheme, weekly free meals, unlimited snacks/drinks, pet-friendly office, monthly team breakfasts/socials, quarterly offsites. Can request to work abroad up to one month per year. - **Team**: Small (~23 people), high-agency, with deep technical talent. - **Open Roles** (as of latest): ML Systems Engineer (Model Training & Infra), Full Stack Product Engineer, Strategy & Operations. ## Sources 1. [cosine.sh](https://cosine.sh/) 2. [cosine.sh/careers](https://cosine.sh/careers) 3. [Y Combinator](https://www.ycombinator.com/companies/cosine) 4. [LinkedIn](https://uk.linkedin.com/company/cosine-ai) 5. [Ashby Jobs](https://jobs.ashbyhq.com/cosine) ## Other roles at Cosine - [Founding Head of Financial Services](https://feeny.ai/job/founding-head-of-financial-services-cosine-london-7tsya8rtm36k) — London, United Kingdom - [Founding Head of Public Sector](https://feeny.ai/job/founding-head-of-public-sector-cosine-london-1entpdng7w7s) — London, United Kingdom