Lead Engineer (Golang)£70,000-£90,000 + Bonus South West London Office-Based (5 Days per Week) Build More Than Software. What if the systems you built helped protect critical infrastructure around the world? We're working with an innovative cyber security company that's scaling rapidly and looking for a Lead Principal Engineer to become the technical right hand to the Head of Development. This is a rare opportunity to shape architecture, influence engineering standards and drive the adoption of AI-assisted development-all while staying hands-on with the code. If you're looking for genuine technical ownership rather than endless meetings, keep reading. The Role You'll sit at the heart of the engineering team, turning business requirements into robust technical solutions and giving developers the clarity they need to build with confidence. Working closely with the Head of Development, you'll shape architectural decisions, own detailed technical design and become the go-to person for technical leadership across the backend team. What You'll Be Doing

• Define technical solutions alongside the Head of Development.
• Own detailed system design and technical specifications.
• Lead backend development using Golang and modern microservices.
• Mentor engineers and raise technical standards.
• Champion secure software engineering and DevSecOps.
• Drive AI-assisted development, from rapid prototyping through to code review.
• Build secure, scalable APIs and distributed systems.
• Improve performance, reliability and engineering quality.

• Strong commercial experience with Golang.
• Expertise building microservices and distributed systems.
• Proven technical leadership experience.
• Strong architecture and systems design skills.
• Experience with Docker, PostgreSQL, MongoDB and secure CI/CD.
• A security-first mindset.
• Confidence mentoring engineers and influencing technical direction.
• Experience using AI to accelerate software delivery.

• Cyber security or regulated industry experience.
• Kubernetes and cloud-native technologies.
• OWASP, ISO 27001 or IEC 62443.
• Open-source contributions.