Senior / Lead Fullstack (React) AI Engineer

Location: London (Hybrid - 3-4 days per week)
Salary: 115,000 - 150,000 + Equity + Excellent Benefits
Job Type: Permanent

We're partnering with an innovative, fast-growing technology company that's redefining how AI-powered products are built and delivered.
This is an exciting opportunity for a Senior / Lead React AI Engineer to join a high-calibre engineering team developing cutting-edge AI applications used by customers globally. You'll play a pivotal role in building intuitive user experiences while integrating the latest advances in Generative AI and agentic systems into production software.

As a Senior / Lead React AI Engineer, you'll take ownership of features from concept through to production, working across both the front end and backend to deliver scalable, high-quality applications.
Working closely with Product Managers, AI Engineers and Software Engineers, you'll help shape technical direction while building intelligent products that leverage Large Language Models (LLMs) and modern AI tooling.

• Design and develop modern, scalable React applications.
• Build backend APIs and services using TypeScript and Node.js.
• Deliver production-ready features across the full software development lifecycle.
• Integrate AI capabilities, LLMs and agentic workflows into customer-facing products.
• Collaborate with AI Engineers to build seamless AI-powered user experiences.
• Champion engineering best practices, testing and code quality.
• Improve application performance, scalability and reliability.
• Mentor engineers and contribute to technical leadership across the team.
• Work closely with cross-functional teams in an Agile environment.

You'll be an experienced software engineer with a passion for building exceptional products and embracing modern AI technologies.
You'll ideally have:

• 8+ years' commercial software engineering experience.
• Strong expertise with React and TypeScript.
• Experience developing backend services using Node.js.
• Experience building scalable APIs and modern web applications.
• Strong understanding of software architecture and engineering best practices.
• Commercial experience working with AWS or Google Cloud Platform (GCP).
• Daily use of AI-assisted development tools such as Claude Code, GitHub Copilot or similar.
• Hands-on experience building or integrating AI-powered applications, LLMs or agentic systems.
• Excellent communication and stakeholder engagement skills.
• A proactive mindset with a passion for delivering high-quality software.

• Vertex AI
• Large Language Models (LLMs)
• Agentic AI
• Docker
• CI/CD
• Infrastructure as Code
• Microservices
• Event-driven architecture

• React
• TypeScript
• Node.js
• AWS
• Google Cloud Platform (GCP)
• Vertex AI
• REST APIs
• Large Language Models (LLMs)
• Agentic AI
• Git
• CI/CD

• 115,000 - 130,000 base salary
• Equity package
• Hybrid working (3-4 days per week in the London office)
• 30 days annual leave plus bank holidays
• Excellent benefits package
• Work on cutting-edge AI products used by customers around the world
• High-performing engineering team with genuine ownership and autonomy
• Excellent opportunities for career growth and technical leadership

Applicants must be based in the UK and have the full right to work in the UK.
Unfortunately, visa sponsorship is not available for this position.