Principal Engineer

PLUXEE UK LTD; Milton Keynes; Hybrid; GBP 110,000 - 135,000; Full time

Job summary

Pluxee seeks a Principal Engineer to provide technical leadership across .NET products and platforms in a hybrid role based in Milton Keynes. You will own end-to-end technical direction, shape architecture, drive governance, and lead cross-team collaboration to deliver secure, scalable software solutions for Payments, Discounts, Benefits and more.

You will stay hands-on with prototypes and reviews, mentor engineers, and ensure the alignment of architecture with business strategy and global

Qualifications

• Extensive experience designing, building and operating enterprise-grade .NET products.
• Strong knowledge of software architecture, patterns and microservices trade-offs.
• Hands-on experience with Azure services and cloud-native patterns.
• Experience modernising legacy .NET applications and integrating APIs.

Responsibilities

• Deliver scalable, secure, resilient and cost-efficient end-to-end technical solutions.
• Provide visible technical leadership that improves engineering quality and delivery confidence.
• Align product technology roadmaps with business strategy and security standards.
• Ensure architecture decisions and documentation are current for governance and audits.
• Act as senior technical authority for product squads and guide complex design decisions.
• Remain hands-on through prototypes, code reviews and targeted delivery of high-value components.
• Partner with Product Owners to translate product outcomes into technical capabilities and user stories.
• Identify risks early with mitigation and clear decision records.
• Establish engineering standards for architecture, testing, observability and security.
• Define guardrails for APIs, data access, monitoring and operational readiness.
• Champion performance engineering and accessibility by design.
• Coach engineers through reviews and communities of practice.
• Lead root-cause analysis and drive systemic improvements into backlogs.
• Maintain architecture repository and lifecycle documentation.
• Lead solution design reviews ensuring alignment with global standards.
• Shape modernisation roadmaps and cloud adoption strategies.
• Improve CI/CD, automated testing and release safety.
• Promote cost-aware architecture and FinOps awareness.
• Lead adoption of reusable components for UK regulatory needs.
• Ensure threat modelling and privacy by design are integrated.
• Work with security and operations to address audit findings and controls.

Skills

C#

ASP.NET Core

RESTful APIs

Distributed systems

Asynchronous messaging

SQL-based data platforms

Azure services

CI/CD

DevSecOps

Threat modelling

Security by design

Architecture governance

Education

Degree in Computer Science or Software Engineering

Tools

Azure

Azure App Service

Azure Functions

Service Bus

Azure SQL

Cosmos DB

Job description

At Pluxee, we shape the world of employee benefits and engagement by bringing to life a personalized and sustainable employee experience, at work and beyond.

Permanent Regular Job Description: The Principal Engineer is the senior individual contributor responsible for technical leadership, solution architecture and engineering excellence across Pluxee UK’s .NET-based digital products and platforms. s a Principle Engineer you will expected to: Own and influence end-to-end technical direction across product discovery, design, delivery and operation. It combines hands‑on engineering with architectural leadership, ensuring that solutions are secure, scalable, resilient, maintainable and aligned with measurable business outcomes. Support and enhance existing internally developed products while shaping new products and platform capabilities across Payments, Discounts, Benefits, Rewards, Salesforce, Business Central, Analytics, mobile applications and web portals. Provide technical direction across squads, establishes engineering guardrails, manages technical debt and ensures adherence to internal governance, audit, security, privacy and accessibility requirements. A key objective is to align the UK technology landscape and product needs with global enterprise standards, strategies and reusable platform capabilities.

YOUR NEXT CHALLENGE

Deliver scalable, secure, resilient and cost‑effective end‑to‑end technical solutions that meet product, business, functional and non‑functional requirements. Provide visible technical leadership that improves engineering quality, delivery confidence, team capability and consistency across squads. Align product technology roadmaps with business strategy, Pluxee enterprise standards, security requirements and global platform direction. Ensure architecture decisions, system documentation and operational controls are current, traceable and suitable for governance and audit. Technical leadership for products and platforms Own and evolve the end‑to‑end technical architecture for .NET digital products and shared platform capabilities. Act as the senior technical authority for product squads, resolving complex design decisions and providing clear, pragmatic technical direction. Remain hands‑on through prototypes, reference implementations, code reviews, troubleshooting and targeted delivery of high‑risk or high‑value components. Partner with Product Owners, Product Managers and Digital Asset Owners to translate product outcomes into coherent technical capabilities, features and user stories. Identify technical risks, dependencies and constraints early, with proportionate mitigation and decision records Engineering excellence and software quality Establish and promote engineering standards covering clean architecture, SOLID principles, secure coding, automated testing, code quality and maintainability. Define guardrails for APIs, event‑driven integration, data access, error handling, logging, monitoring and operational readiness. Champion performance engineering, resilience testing, accessibility by design and production supportability. Coach engineers and technical lead through design reviews, pairing, code reviews and communities of practice Lead root‑cause analysis for complex technical issues and ensure systemic improvements are captured in product backlogs. Architecture governance and documentation Maintain an accurate architecture repository and system inventory covering applications, integrations, infrastructure, data flows, technology standards and lifecycle status. Produce and maintain solution context, container, component, deployment, sequence, integration and data‑flow views at an appropriate level of detail. Document significant decisions using architecture decision records and ensure designs remain traceable to product and non‑functional requirements. Lead solution design reviews and assure country‑specific solutions against Pluxee global enterprise architecture and security standards. Modernisation, cloud and DevOps Shape modernisation roadmaps for legacy .NET applications, including incremental decomposition, API enablement, cloud adoption and technical debt retirement. Guide the appropriate use of Azure services, containers, application services, messaging, API management, relational and NoSQL data platforms. Improve continuous integration, continuous delivery, automated quality controls, infrastructure management, observability and release safety. Promote cost‑effective architecture and operational practices, including capacity planning, service ownership and FinOps awareness. Lead the adoption of reusable global components and shared platforms where they meet UK product and regulatory needs Security, compliance and operational integrity Ensure threat modelling, secure design, privacy by design, vulnerability management and data protection controls are integrated into engineering ways of working. Work with security, risk, architecture and operations stakeholders to address audit findings and maintain evidence of appropriate controls. Define non‑functional requirements and acceptance criteria for availability, recoverability, performance, security, accessibility and support. Ensure technical designs include suitable monitoring, alerting, backup, disaster recovery and incident response considerations.

YOU ARE A MATCH IF...

Education: A degree in Computer Science, Software Engineering or related discipline, or equivalent professional experience. Relevant Microsoft Azure or architecture certifications are advantageous. Work Experience: Extensive experience designing, building and operating enterprise‑grade .NET products, with demonstrable technical leadership across multiple delivery teams or complex platforms. Deep practical knowledge of C#, modern .NET, ASP.NET Core, RESTful APIs, distributed systems, asynchronous messaging and SQL‑based data platforms. Experience modernising legacy .NET Framework applications, including MVC, Entity Framework, T‑SQL, stored procedures, Web API, SOAP and WCF integrations. Strong knowledge of software architecture and design patterns, domain‑driven design, modular architecture, microservices trade‑offs, integration patterns and API lifecycle management. Hands‑on experience with Azure services such as App Service, Functions, Service Bus or queues, API Management, Azure SQL, Cosmos DB, containers and monitoring services. Strong understanding of CI/CD, automated testing, code quality controls, observability, incident diagnosis, reliability engineering and DevSecOps practices. Knowledge of application security, identity and access management, OWASP guidance, threat modelling, privacy by design and relevant compliance requirements. Experience producing high‑quality architecture artefacts, including context and container views, integration diagrams, data‑flow diagrams, deployment views, technology roadmaps and architecture decision records. Ability to communicate complex technical issues clearly to engineers, product stakeholders, senior leaders, auditors and suppliers.

Desirable technical skills: Experience in payments, prepaid cards, employee benefits, rewards, vouchers, cashback or regulated financial services. Experience with frontend or cross‑platform technologies such as Blazor, modern JavaScript frameworks or .NET MAUI. Experience operating in a multi‑country enterprise and integrating global platforms with country‑specific products. Understanding FinOps, cloud cost optimisation, accessibility standards and software supply‑chain security. Languages: Fluent English; French is advantageous. Location Hybrid - Milton Keynes office.

Why join Pluxee?

Join an inclusive team Work at the heart of the community alongside 5,000 experts across 29 countries - we embrace diversity and value uniqueness, fostering a workplace where everyone can thrive. Turn inspiration into possibility Get space to try new ideas, experiment and move the world of work forward as you bring new digital experiences - and moments of connection - to millions of people. Make a positive impact Touch millions of lives and create meaningful change for people and the world we share, supporting our commitments to diversity, sustainability, and local economies. Grow with us Get support you need to take meaningful steps in your career, whether you're performing your work/life balance or learning new skills.