Senior Software Engineer

A growing SaaS business is hiring a Senior Software Engineer to lead the technical rebuild of its flagship product. This is a hands-on role for an experienced engineer who loves modernising legacy systems and is excited about using AI tools to accelerate design, refactoring, and delivery .

You’ll be the technical driver behind a full product transformation, rebuilding a complex ERP-scale system into a modern, cloud-native platform. Working closely with product and technical leadership, you’ll design architecture, write production-quality code, and use AI tools to streamline development and shape how the next generation of the product is built.

Role: Senior Software Engineer (AI-Enabled Refactor)

Salary: Up to £70,000 per annum (flexible for exceptional candidates)

Location: Hybrid – London office once per fortnight, remote within the UK

What you’ll be doing:

• Lead the refactor of a large legacy system into a modern, scalable cloud-native product
• Design and implement new architecture using AWS microservices, PostgreSQL, Node.js, React, and TypeScript
• Use AI-assisted tools such as OpenAI, LangChain, Claude, or Hugging Face to enhance efficiency, code quality, and testing
• Establish clean engineering practices, including CI/CD, automation, and testing frameworks
• Work closely with product and technical leadership to translate business requirements into technical outcomes
• Mentor a junior developer and help shape future engineering capability

What you’ll need:

• 7+ years’ experience building or refactoring large-scale applications (ERP or SaaS experience ideal)
• Strong technical background with Python, TypeScript, React, Node.js, PostgreSQL, and AWS
• Proven experience in greenfield development and system modernisation
• Interest or hands-on experience with AI-driven development tools
• Solid understanding of clean architecture, automation, and modern DevOps practices
• A collaborative mindset and enthusiasm for innovation

What’s on offer:

• Salary up to £70,000 per annum (flexible for the right person)
• Hybrid working – typically remote with occasional team days in London
• Opportunity to lead a full-scale rebuild project from the ground up
• Freedom to experiment with AI technologies that accelerate development
• Startup-style autonomy backed by the stability of a well-funded organisation

If you’re a senior engineer who enjoys modernisation projects and wants to work at the intersection of AI and large-scale software engineering , this is an opportunity to build something that defines the next generation of a leading SaaS platform.