Principal Engineer

Join the Mission

We are a fast‑growing startup building scalable, high‑quality digital products at pace. Our success depends on strong engineering foundations, pragmatic architecture, and ways of working that enable teams to deliver value continuously.

About the Opportunity

• As a Principal Engineer, you will act as a senior technical and engineering practice leader within the organisation; mentoring and guiding engineers across multiple disciplines.
• You will set direction for engineering process, standards, and ways of working across the architecture and engineering teams.
• You will work closely with solution architects, business analysts, technical product managers, and delivery teams to improve flow, quality, and consistency while remaining pragmatic and delivery focussed.
• This role balances hands‑on technical leadership with organisational influence, helping teams make good engineering decisions as autonomy increases.

What You’ll Be Doing

• Lead the definition and evolution of engineering principles, standards, and guardrails across teams.
• Embed effective engineering ways of working, including; Agile and lean delivery practices, Modern DevOps and CI/CD approaches, pragmatic documentation and decision‑making in line with security requirements.
• Ensuring solutions meet stringent security and compliance requirements
• Partner with (coach/mentor) architects to ensure architectural decisions are implementable, scalable, and aligned with delivery realities.
• Identify systemic friction in the engineering lifecycle and design improvements that increase flow, quality and developer experience.
• Act as a senior escalation point for complex technical and architectural challenges e.g. performing design and build assurance reviews and shaping technical roadmaps.
• Influence technology choices with a long‑term mindset while remaining sensitive to delivery or security constraints.

What You’ll Bring

• Significant experience operating at Principal Engineer or equivalent technical leadership level.
• Experience in adhering compliance standards such as ISO 27001, Cyber Essentials/CES+, NIST, or equivalent.
• Strong understanding of modern software engineering practices, including cloud‑native architectures and distributed systems.
• Proven experience shaping or evolving engineering process and ways of working across multiple teams.
• Proven technical and leadership skills in the following areas:

1. Cloud expertise - hands‑on architecting or operating cloud, private cloud or virtualised environments.
2. Security & Public Sector – familiarity with secure system design, zero‑trust principles and government security classifications.
3. Infrastructure & Networking – strong understanding of networking, firewalls, routing, VPNs, SD‑WAN and identity management.
4. Modern Engineering practice – IaC (e.g. Terraform, ARM, CloudFormation), CI/CD pipelines (e.g. Azure DevOps, GibHub Actions, Jenkins, GitLab) and containerisation (Docker, Kubernetes)
5. Software Engineering – solid understanding of API Design, micro‑services and integration patterns.

• Ability to influence across disciplines (engineering, architecture, product) without relying on hierarchy.
• Excellent communication skills, with the ability to explain complex technical concepts clearly to varied audiences.
• A pragmatic, outcome‑focused mindset with a bias towards action and continuous improvement.

Bonus Points For

• Experience helping new companies scale‑up and move from early‑stage to more mature engineering practices.
• Exposure to platform engineering, developer experience, or internal tooling.
• Experience operating in environments with evolving product direction and technical uncertainty.
• Passion for building inclusive, high‑performing engineering cultures.
• Strong problem‑solving ability in fast‑paced, multi‑project environments.
• Existing UK Government Security Clearance (SC or above)

Clearance Requirements:

This role requires either an existing Security Clearance (SC level) or for one to be passed before commencement. There must be a willingness to undergo Developed Vetting (DV).

Work Location

Hybrid remote in London

Job Types

Temporary, Fixed term contract (outside of IR35)

Screener Questions:

1. Do you hold UK nationality? (Required due to client security restrictions)
2. Do you currently hold active UK SC clearance?
3. Are you eligible and willing to undergo UK SC/DV clearance for this role? (Applications without this cannot be considered)
4. Does your delivery approach allow for on‑site presence in London when required (typically around 3 days per week)?

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