Senior Software Engineer

Full-Stack Product Engineer | Series A AI Startup

Central London (4 days in office

£80,000 - £130,000 + equity

Visa Sponsorship: Available

We're working with a recently Series A-funded AI startup that's building technology to transform how large organisations manage complex, business-critical operations.

The business is already seeing impressive commercial traction, securing significant enterprise contracts and attracting customers in a traditionally difficult-to-disrupt market.

With fresh investment, a small, highly technical team and ambitious plans for international growth, they're now looking for a Senior Full-Stack Product Engineer to play a key role in building and scaling their AI-powered platform.

This isn't a role where you'll be working on a small part of a much larger system. You'll have genuine end-to-end ownership, working across the frontend, backend and AI layers to build products that solve real customer problems.

You'll work directly with the founders, engineers and product team, helping shape technical decisions, influence product direction and take ideas from concept through to production.

It's an opportunity for someone who loves building, enjoys solving difficult technical problems and wants to work at the forefront of applied AI.

What You'll Be Doing

• Design, build and ship full-stack product features, taking ownership from initial concept through to production.
• Develop intuitive, high-quality user interfaces using React and TypeScript.
• Build scalable backend services and APIs using Node.js, ensuring reliability, performance and maintainability.
• Integrate large language models, AI agents and machine learning capabilities into real-world product workflows.
• Work on challenging AI problems involving document processing, computer vision, data extraction and intelligent automation.
• Develop systems for evaluating and improving AI performance, including prompt optimisation, model fine-tuning and automated testing.
• Collaborate closely with the founders, product team and other engineers to turn customer problems into effective technical solutions.
• Contribute to architectural decisions, infrastructure, CI/CD and engineering best practices as the platform scales.
• Continuously explore emerging AI technologies and identify opportunities to improve product capabilities, accuracy and performance.

Who I'm Looking For

• A strong background in full-stack or product engineering, ideally within a high-growth startup or B2B SaaS environment.
• Excellent hands-on experience with TypeScript, React and Node.js, with the ability to work confidently across the entire stack.
• Practical experience building and deploying AI-powered applications, ideally involving LLMs, AI agents or machine learning.
• Exposure to prompt engineering, model evaluation, fine-tuning or computer vision.
• Strong understanding of backend architecture, APIs, scalability and building reliable production systems.
• A product-focused mindset, with the ability to understand customer problems and translate them into well-designed technical solutions.
• Comfortable taking ownership of projects, making technical decisions and shipping high-quality code independently.
• Someone who enjoys working in a fast-paced environment where priorities can evolve and decisions are made quickly.
• Excellent problem-solving skills, intellectual curiosity and a genuine interest in the latest developments in AI.

Most importantly, I'm looking for someone who genuinely loves building products. Someone who is equally comfortable discussing technical architecture, writing production code and thinking about how a feature will actually be used by customers.

You don't need to have worked in a particular industry, but you should be excited by the opportunity to apply AI to complex, real-world problems.

If you're a strong full-stack engineer who enjoys building products, experimenting with AI and taking real ownership of your work, I'd be keen to speak.