Principal Engineer - BackEnd - AI

Principal Engineer - Backend Platform (AI) About the OpportunityOur 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.This is a senior individual contributor role for an engineer who enjoys solving complex architectural problems, influencing engineering strategy and raising the technical bar across multiple teams.The RoleAs 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.Key ResponsibilitiesTechnical Strategy & ArchitectureDefine 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.Distributed Systems & Platform EngineeringDesign 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.Hands-on Technical LeadershipRemain 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.Engineering ExcellenceMentor 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.Cross-Functional LeadershipPartner 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.Required Experience12+ 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.Technical ExpertiseCandidates should demonstrate deep expertise in several of the following areas:Backend EngineeringPython, Java or GoREST APIs and gRPCMicroservices architectureHigh-performance backend servicesDistributed SystemsEvent-driven architectureMessaging and streaming platforms (Kafka, Azure Service Bus or equivalent)Service communication patternsConsistency modelsFault tolerance and resiliencyCloud & InfrastructureAzure, AWS or Google CloudKubernetesDockerInfrastructure as CodeCI/CD pipelinesData PlatformsPostgreSQLRedisObject storageData pipelinesDatabase optimisationReliability EngineeringObservabilityMonitoring and alertingDistributed tracingSLOs and error budgetsIncident managementSecurityIdentity and access managementSecrets managementZero Trust architectureNetwork securityEnterprise platform securityPreferred ExperienceExperience in one or more of the following would be highly advantageous:Enterprise platform engineeringAI infrastructure or AI platform engineeringLarge-scale SaaS environmentsFinancial Services, Public Sector or other regulated industriesPlatform-as-a-Product organisationsHigh-scale cloud-native systemsPersonal AttributesThe successful candidate will demonstrate:Exceptional technical judgementSystems thinking and architectural leadershipStrong problem-solving capabilityBias for action and ownershipExcellent mentoring and coaching skillsPragmatic decision makingPassion for engineering excellenceAbility to influence without direct authorityWhy Join?This is an opportunity to shape the technical foundations of a large-scale AI platform, working alongside world-class engineers to solve complex distributed systems challenges. You will influence engineering strategy across the organisation while remaining deeply technical and hands-on, helping define the architecture that powers the next generation of AI-enabled products