Principal Engineer - BackEnd - AI

About the Opportunity

Our client is building a next-generation AI platform that powers mission-critical applications at enterprise scale. They are looking for an exceptional Principal Backend Engineer to define the technical direction of the backend platform that underpins AI products, distributed systems and cloud infrastructure across the organisation.

As Principal Engineer, you will provide technical leadership across backend architecture, distributed systems, cloud infrastructure and platform engineering.

Working alongside Engineering Managers, Staff Engineers and Product Leaders, you will shape long-term technical strategy, resolve complex engineering challenges and establish the architectural standards that enable multiple teams to build reliable, scalable systems.

This role is focused on technical leadership rather than people management. Success will be measured by the quality of your technical judgement, the impact of your architectural decisions and your ability to elevate engineering across the organisation.

• Define the technical vision for the backend platform across multiple engineering teams.
• Lead architecture decisions relating to distributed systems, APIs, event-driven platforms and cloud infrastructure.
• Establish engineering standards, architectural principles and best practices for scalable backend services.
• Design resilient, secure and highly available systems capable of supporting enterprise-scale AI workloads.
• Evaluate technology choices and infrastructure investments to ensure long-term scalability and operational efficiency.
• Design and optimise event-driven architectures using modern messaging and streaming technologies.
• Shape data platform architecture, including databases, caching, storage and data processing pipelines.
• Define service boundaries, communication patterns and reliability strategies across distributed applications.
• Drive improvements in platform scalability, performance, observability and resilience.
• Ensure systems are designed with security, reliability and operational excellence as core principles.

• Remain actively involved in architecture, code reviews and technical design discussions.
• Build prototypes and reference implementations to validate architectural decisions.
• Resolve the most complex cross-team engineering challenges.
• Lead architecture reviews, incident post-mortems and technical design sessions.
• Guide engineering teams through major platform and infrastructure initiatives.
• Mentor senior engineers and help develop the next generation of technical leaders.
• Define engineering standards, coding practices and architectural governance.
• Support senior technical hiring through interview design and candidate evaluation.
• Promote a culture of continuous improvement, technical curiosity and engineering excellence.

• Partner with Engineering, Product, Platform, Infrastructure, Security and AI teams to align technology strategy.
• Communicate technical direction and trade-offs to both technical and executive stakeholders.
• Collaborate with external technology partners and vendors where appropriate.
• Contribute to long-term platform and engineering strategy.

• 12+ years' experience in backend software engineering, platform engineering or distributed systems.
• Proven experience operating at Staff or Principal Engineer level within complex technology organisations.
• Strong track record designing large-scale distributed systems and cloud-native platforms.
• Expert knowledge of backend engineering principles, architecture and software design.
• Extensive experience leading technical direction across multiple engineering teams.
• Strong mentoring experience with senior engineers and technical leaders.
• Excellent written and verbal communication skills.

Candidates should demonstrate deep expertise in several of the following areas:

• Python, Java or Go
• REST APIs and gRPC
• High-performance backend services

• Event-driven architecture
• Messaging and streaming platforms (Kafka, Azure Service Bus or equivalent)
• Service communication patterns
• Fault tolerance and resiliency
• Azure, AWS or Google Cloud
• Docker
• Infrastructure as Code

• Redis
• Object storage

• Observability
• Monitoring and alerting
• Distributed tracing
• SLOs and error budgets

• Identity and access management
• Secrets management
• Zero Trust architecture
• Network security

Experience in one or more of the following would be highly advantageous:

• AI infrastructure or AI platform engineering
• Large-scale SaaS environments
• Financial Services, Public Sector or other regulated industries
• Platform-as-a-Product organisations

The successful candidate will demonstrate:

• Exceptional technical judgement
• Systems thinking and architectural leadership
• Strong problem-solving capability
• Bias for action and ownership
• Excellent mentoring and coaching skills
• Pragmatic decision making
• Ability…