Principal Software Engineer — AI‑Led Delivery Leader

SimplyBiz PLC; Greater London; Hybrid; GBP 90,000 - 140,000; Full time

Job summary

Defaqto is hiring a Principal Software Engineer in London to shape how we build software. You will lead the shift from AI-assisted coding to AI-led delivery, own high‑risk initiatives, and set engineering standards across the Technology function.

The role reports to the Head of Engineering with close collaboration to the CTO and product teams. You will guide squads, influence architectural decisions, and champion modern practices for reliability, security and governance in a regulated data

Qualifications

• Substantial commercial software engineering experience at staff/principal level or equivalent.
• Hands-on engineering ability in a modern stack (.NET/C#, TypeScript, Azure, Python, PHP).
• Experience leading agentic/AI-assisted development in production.
• Clear view on engineering practices for AI-led delivery: specs, tests, reviewer workflows, and quality control.
• Ownership of engineering standards across multiple teams.

Responsibilities

• Lead the shift from AI-assisted coding to AI-led delivery across squads.
• Define and codify engineering standards across Defaqto Technology.
• Own end-to-end initiatives with high technical risk or upside.
• Partner with Product to translate business ideas into technical roadmaps.
• Guide squads on architecture decisions and evolution of the tech stack.
• Be a strategic sounding board to leadership while staying hands-on.

Skills

Hands-on engineering

.NET/C#

TypeScript

Azure

Python

PHP

SQL

Data tooling

AI‑led development

Tools

Azure

SQL

Job description

Defaqto is hiring a Principal Software Engineer in London to shape how we build software. You will lead the shift from AI-assisted coding to AI-led delivery, own high‑risk initiatives, and set engineering standards across the Technology function.

The role reports to the Head of Engineering with close collaboration to the CTO and product teams. You will guide squads, influence architectural decisions, and champion modern practices for reliability, security and governance in a regulated data