Principal Software Engineer
Location: London (Hybrid – approx. 1–2 days per month onsite)
Contract: Permanent, Full-time
Package: £80,000–£100,000 + 10% bonus + 10% share options + benefits
Eligibility: UK Security Clearance (SC) eligibility required
The Opportunity
We’re working with a specialist cloud and platform engineering consultancy that partners with organisations across regulated and public-sector environments to modernise how software is built and operated.
The business is expanding its software engineering capability and is hiring a Principal Software Engineer to play a key role in shaping technical direction, delivery standards, and engineering best practices across multiple engagements.
This is a hands-on leadership role suited to an experienced engineer who enjoys operating across architecture, design, and delivery, while mentoring teams and working closely with stakeholders.
As a Principal Software Engineer, you will:
* Lead the design and delivery of modern, scalable, cloud-native software systems
* Shape architecture, service boundaries, and system decomposition using best-practice approaches
* Work hands-on across the stack, with a strong focus on React-based applications
* Guide teams on testing strategy, automation, and developer productivity
* Support customers in reducing technical debt and improving long-term maintainability
* Collaborate closely with cloud and platform engineering teams to deliver end-to-end solutions
* Act as a senior technical advisor, supporting decision-making and technical trade-offs
* Contribute to shared engineering standards, patterns, and ways of working
About You
You’re a senior/principal-level engineer with strong architectural judgement and a consulting mindset. You’re comfortable leading technical conversations, influencing delivery decisions, and working directly with customers.
You’ll bring:
* Strong experience with Domain-Driven Design (DDD) and modern system decomposition
* Proven delivery of microservice-based architectures
* Deep hands-on experience with Java/Spring and React
* Experience improving engineering effectiveness through testing strategy and automation
* Exposure to cloud-native environments (AWS preferred)
* Confidence mentoring engineers and leading technical discussions
* Comfort working with stakeholders in regulated environments
* Eligibility for UK Security Clearance (British citizenship required)
Core technologies:
* Java / Spring
* React / JavaScript
* SQL / NoSQL databases
* Docker / Kubernetes
* AWS
* Playwright
* GitLab, Maven
Nice to have:
* GovUK UI Framework
* Azure or GCP
* .NET
Benefits
* Flexible working with core hours
* Hybrid working model
* 25 days holiday + bank holidays + birthday off
* Enhanced parental leave
* Private healthcare (with family cover options)
* Pension with salary sacrifice
* Mental health and wellbeing support
* Cycle to Work & Electric Car schemes