Full Stack Product Engineer

About the Company

Cosine is the UK's frontier AI lab for autonomous software engineering. We build our own models, agent stack, eval harnesses, and product layer to deliver reliable, enterprise-grade coding performance in security-critical settings for industries including defence, financial services, and healthcare.

Responsibilities

• Build end-user products including command line interfaces, web applications, and platform capabilities
• Integrate products with Cosine platform APIs
• Enable developers to use advanced language models to augment workflows
• Collaborate closely with research to explore and validate new product experiences
• Translate emerging model capabilities into concrete, user-facing features
• Maintain high standards for performance, reliability, and usability

Requirements

• 5+ years of experience building production-grade software
• Experience building reactive, highly interactive applications using React, Svelte, or Vue
• Strong experience with TypeScript and modern frontend frameworks
• Experience designing and consuming REST APIs
• Experience with backend development
• Experience with developer tooling and CI/CD pipelines
• Experience with containerization (Docker)
• Ability to work onsite in our Hoxton, London office five days a week

Preferred Qualifications

• Experience with CLI application development
• Knowledge of Node.js, Python, or Go
• Familiarity with Kubernetes, GCP, and monitoring tools like Grafana or Datadog
• Experience shipping complex applications to technical users

Benefits

• Competitive salary and equity/share options
• 30 days holiday plus bank holidays
• Genuine 9–5 working hours
• Dog-friendly office
• Weekly team breakfast and lunch
• Monthly socials
• Pension scheme
• High-quality equipment