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Posted 12 August, 2026

Principal Software Engineer

Profile 29
London, ENG, GB Full Time

Job Description

Principal Software Engineer

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  • Salary to £80k, poss. higher for their ‘Unicorn’ candidate
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  • Role can be based remotely, as long as you can occasionally travel to London for client work (travel expenses paid) - approx. once a month.
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NB: Please only apply if you are a UK National, have resided in the UK for the past 5 years and are prepared to go through UK SC Security Clearance. Proof of ID will be required prior to interview.

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This role is with a growing is a technology consultancy. This is a hands-on principal engineering role: architecture ownership across multiple services, technical leadership across teams, and direct contribution to engineering standards and hiring. Their successful candidate will be writing code as well as setting direction - this is not a purely architectural or management position. Current delivery is a Java/Spring Boot microservices platform on AWS EKS, with a Next.js frontend and Camunda-based process orchestration.

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Essential

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Experience level: 10+ years minimum, principal or staff grade equivalent.

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Backend and cloud:

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Java 17 or 21, at expert level - modern language features

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Spring Boot in depth: security, transaction management, async/reactive

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Microservices architecture design - has designed services from scratch

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Kubernetes and Docker in production (not local development use)

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AWS, hands-on: EKS, Lambda, S3, RDS, EventBridge

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CI/CD pipeline ownership

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Automated testing discipline: JUnit, Mockito, integration testing, TDD or BDD

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Frontend:

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Held a lead or tech lead role on frontend development in React. Leadership must have been over React work itself.

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Understands and has implemented FFE/BFE separation - the split between the presentation layer (components, styling, client state) and the frontend's own server-side tier (data aggregation for the UI, session and auth handling, server-side rendering, API route composition).

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Leadership:

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Architecture ownership across multiple systems

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Cross-team technical leadership

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Track record of influencing engineering standards, technology choices, or hiring

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Evidence of growing other engineers

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Security clearance: UK SC clearance required. Active clearance strongly preferred; eligible candidates considered - must be a UK national with 5+ years continuous UK residency.

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Desirable:

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Camunda 8 / BPMN process orchestration

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Next.js specifically (App Router, server components, route handlers)

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Terraform or other infrastructure-as-code, to module-authoring level

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React Native or equivalent — building native mobile from a React codebase

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Design system or component library ownership

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Consultancy or client-facing delivery background

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Open-source contributions, conference talks, or published technical writing

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Polyglot beyond Java

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Other Stuff

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NB: for non-UK Citizens; we cannot accept applications from anyone requiring sponsorship (now or in the future) for UK permanent employment status. If you are utilising a work visa this must allow you to work in the UK unrestricted for at least the next 5 years.

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Profile 29 recruitment keywords: Java Spring Boot Microservices Kubernetes Docker AWS EKS Lambda S3 RDS EventBridge CI/CD Junit Mockito integration testing TDD BDD React Camunda BPMN Next.js Terraform lead senior manage manager director remote London hybrid developer engineer

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