Principal Systems Engineer

ECI has an exciting opportunity for an experienced Principal Systems Engineer to join our London team. In this role, you will play a pivotal role bridging strategic design and hands-on delivery. This individual will lead the design and architecture of client solutions, working with our Technical Architecture team on high-level design (HLD), and driving low-level design (LLD), while also providing expert consultancy and engineering delivery. The EA will act as a trusted advisor to clients, ensuring that solutions are technically sound, aligned with business goals, and delivered effectively. This role requires a strong background in Microsoft 365, cloud platforms, and enterprise infrastructure, with the ability to operate independently, whilst working closely with our Technical Architecture, Client Technology and Senior Engineering Teams. Regular face-to-face contact with internal stakeholders, engineers and clients is essential to the success of this role.

This is a hybrid role with a strong preference for candidates to be based in the London area.

What you will do: Client & Team Engagement

• Act as a trusted advisor to clients, engaging consultatively to understand goals, technical challenges, and strategic priorities.
• Lead client-facing workshops and architecture sessions to define solution roadmaps and technical direction.
• Provide mentorship and technical guidance to internal teams, promoting knowledge sharing and architectural best practices.
• Collaborate cross-functionally with Technical Architects, Client Technology Managers, Project Managers, and Engineering teams to add value and ensure alignment and delivery excellence.

Architecture & Design

• With a deep familiarity and knowledge of the client environment, own the low-level design (LLD) process, ensuring scalability, security, and performance.
• Working with Technical Architects on High-level designs (HLD), translating business and technical requirements into architectural blueprints and implementation plans.
• Maintain architectural oversight across the project lifecycle, ensuring adherence to standards and design integrity.
• Evaluate and recommend technologies, platforms, and tools that align with client needs and enterprise strategy.
• Produce high-quality documentation including architecture diagrams, design specifications, and technical standards.

Engineering Delivery

• Draft and present complex, multi-phase Changes to technical and non-technical stakeholders.
• Participate in, and where required lead, client and internal TABs and CABs.
• Lead technical delivery of infrastructure and cloud transformation projects, ensuring timely and quality outcomes.
• Troubleshoot complex technical issues across cloud, networking, and security domains, providing resolution and root cause analysis.
• Contribute to continuous improvement by identifying opportunities to optimise delivery processes and technical standards.

• Proven experience in enterprise IT architecture, consultancy, and hands-on delivery
• Strong client engagement skills with the ability to lead workshops and present to technical and non-technical audiences
• Deep expertise in Microsoft 365 and Azure, with a focus on solution design and implementation
• Strong documentation and communication skills, including HLD/LLD and technical standards
• Experience working across project delivery, engineering, and architecture teams
• Ability to operate independently while collaborating effectively with internal stakeholders
• Familiarity with change management processes including CAB/TAB participation
• Experience in a Managed Service Provider or financial services environment preferred
• Certifications in Microsoft cloud technologies or enterprise architecture frameworks desirable

ECI's culture is all about connection - connection with our clients, our technology and most importantly with each other. In addition to working with an amazing team around the world, ECI also offers a competitive compensation package and so much more! If you believe you'd be a great fit and are ready for your best job ever, we'd like to hear from you!

ECI is the leading global provider of managed services, cybersecurity, and business transformation for mid-market financial services organizations across the globe. From its unmatched range of services, ECI provides stability, security and improved business performance, freeing clients from technology concerns and enabling them to focus on running their businesses. More than 1,000 customers worldwide with over $3 trillion of assets under management put their trust in ECI. At ECI, we believe success is driven by passion and purpose. Our passion for technology is only surpassed by our commitment to empowering our employees around the world.