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 is the UK's frontier AI lab for autonomous software engineering. 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.

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.

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.

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.

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 with 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.

Skills & Experience:

• 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.
• Strong communication skills, with the ability to work effectively with technical and non-technical customer stakeholders.
• Experience building reactive, highly interactive applications (React, Svelte, Vue).
• Experience with backend development and designing and consuming REST APIs.
• Strong experience with TypeScript and modern frontend frameworks.
• Knowledge of Node.js, Python, and Go is a plus.
• Familiarity with CI/CD pipelines and containerization.

You Might Thrive in This Role If You:

• Have 5+ years of experience building production-grade software.
• Are comfortable building highly interactive web or IDE-based experiences using modern frameworks.
• Enjoy working directly with customers, understanding their needs, and taking responsibility for making solutions work in their environments.
• Care deeply about developer experience, performance, and reliability.
• 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.

Compensation, Benefits & Ways of Working:

• Competitive salary, benchmarked to the market.
• Equity / share options.
• 30 days’ holiday + bank holidays.
• Genuine 9-5 working hours.
• Dog-friendly office.
• Weekly team breakfast & lunch.
• Monthly socials.
• Pension.
• High-quality equipment to do your best work.

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.