Principal Engineer I, Prepurchase Platform

Job Summary: JOB DESCRIPTION – Principal Engineer I, Prepurchase Platform Location: London, UK Division: Ticketmaster UK Limited Line Manager: VP Engineering, Accounts, Identity and Pre-Purchase Contract Terms: Full-time permanent, 40h/per week THE TEAM The Prepurchase Platform group owns the backend services that power every fan's path to a ticket. We handle event discovery, real-time seat availability, and interactive venue experiences at massive scale, processing billions of API calls during peak on-sales. Our engineers build systems that must be fast, resilient, and available when it matters most. THE JOB As a Principal Engineer on the Prepurchase Platform team, you will write code, build systems, and solve hard problems hands-on. This is a systems thinking role: you will reason carefully about distributed systems tradeoffs, understand why existing designs exist before proposing changes, and act on problems without waiting to be asked. You will lead platform modernization efforts, design event-driven architectures, and deliver systems that remain resilient during the highest-demand on-sales, working across multiple teams within the Prepurchase domain rather than within a single service area. The platforms you work on have no single correct implementation; they are a continuous series of tradeoff decisions made under real constraints. Your value comes from understanding those tradeoffs clearly and improving them deliberately, not from implementing solutions in a vacuum. This is a hands-on technical role with no direct reports. You will write production code daily, influence technical direction, and partner with teams across Ticketmaster on cross-cutting architectural decisions. Depending on team needs, you may embed deeply within a single service area or work horizontally across multiple teams, the role flexes to where the highest-impact work is. WHAT YOU WILL BE DOING Identify and act on production problems without being prompted. A single 500 error reaching a fan is a problem, not a data point; treat it accordingly and act with urgency regardless of volume. Build end-to-end, high-availability systems that handle extreme traffic spikes during high-demand on-sales without degradation. Lead platform modernization initiatives - migrating legacy services to cloud-native, microservice-based architectures. Design and implement streaming and event-driven solutions using Kafka/gRPC, enabling real-time data flow across services. Embed deeply in a specific service area when needed, or work horizontally across teams to solve cross-cutting problems. Champion resilience patterns: circuit breakers, graceful degradation, bulkheads, and auto-scaling strategies. Collaborate with the Enterprise Architecture team on architectural decisions and evolve engineering standards across the Prepurchase domain. Partner with product, security, and SRE teams to align technical decisions with business priorities. Drive observability improvements - ensuring services are instrumented for monitoring, alerting, and rapid incident response. Identify and eliminate single points of failure, improving system reliability and reducing on-call burden. Apply AI and machine learning tools to improve developer productivity, automate operational tasks, and enhance system capabilities. Evaluate and introduce new technologies that improve performance, reliability, or engineering velocity. WHAT YOU NEED TO KNOW (or TECHNICAL SKILLS) Proven ability to reason about distributed systems tradeoffs - scalability, consistency, availability, latency and make defensible design decisions under real constraints. This is the core bar for this role. Proven experience writing production code and building high-traffic systems at scale - this is a coding role first. Expertise in Java (17+); and the JVM, with strong command of JVM internals, garbage collection behavior, and performance tuning under load. Kotlin is a plus. Hands-on experience with a reactive, non-blocking framework (Vert.x, Spring WebFlux, or equivalent) and asynchronous, event-driven service design. Deep experience with stream processing and event-driven architecture - Kafka Streams, Apache Flink, or equivalent - including stateful streaming, topology design, and managing local state stores (e.g. RocksDB) at scale. Proven track record building high-throughput, low-latency systems where tail latency, backpressure, and memory pressure are first-class design concerns. Strong command of gRPC (including streaming RPC) and binary serialization formats such as FlatBuffers, Avro, or Protobuf, with schema evolution via a registry. Familiarity with Data-Oriented Design (DoD) - structuring code around how data is laid out, accessed, and transformed for cache efficiency and throughput, rather than around object hierarchies. Experience with compact, search-oriented data structures (e.g. RoaringBitmap, succinct/bitset representations) for representing large in-memory state efficiently. Experience with search engines (Elasticsearch, Solr) for discovery workloads is a plus. Strong grasp of microservice design, service mesh (Istio/Envoy), API contract evolution, and backend-for-frontend patterns, including GraphQL APIs and WebSocket subscriptions for real-time client delivery. Hands-on experience with AWS (EKS) and cloud-native operations - containerization (Docker, Kubernetes), packaging and deploy tooling (Helm, Kustomize), and infrastructure-as-code (Terraform) Proficiency with caching strategies (Redis, CDN layer caching) and their application to high-traffic systems. Solid understanding of CI/CD pipelines (GitLab CI), and progressive deployment strategies (blue-green, canary). Experience designing for high availability - mult-region active-active/active-passive architectures, failover strategies, disaster recovery and systems that remain stable under adversarial load and abuse. Proficiency with AI/ML tools and techniques - using LLMs, AI-assisted development, and automation to accelerate engineering workflows and improve system intelligence. Familiarity with observability tooling: Grafana, Splunk, Prometheus, OpenTracing, or equivalent. Strong understanding of security best practices - OAuth/OIDC, input validation, secrets management. Track record of leading technical initiatives across multiple teams without direct authority. YOU (BEHAVIOURAL SKILLS) Systems Thinking: Understands distributed systems as a set of tradeoffs, not a set of correct answers. Understands that failures emerge from system interactions and missing feedback loops - not just broken components. Evaluates designs by asking why they exist and what constraints shaped them, not just whether they match a preferred pattern. Technical Vision: Anticipates platform challenges and designs systems that scale ahead of demand. Domain Depth: Before changing a system, invests in understanding it fully - its history, the teams and services it interacts with, the constraints that shaped its current design, and the forces Ownership: Takes end-to-end responsibility for system health, performance, and reliability across the Prepurchase domain. Influence Without Authority: Drives architectural decisions and engineering standards through collaboration, not hierarchy. Communication: Explains complex technical trade-offs clearly to both engineering peers and non-technical stakeholders. Composure Under Pressure: Stays calm during high-severity incidents and high-demand on-sales, delivering clear resolutions. Continuous Improvement: Identifies opportunities to modernize, simplify, and strengthen systems - and follows through. LIFE AT TICKETMASTER We are proud to be a part of Live Nation Entertainment, the world’s largest live entertainment company. Our vision at Ticketmaster is to connect people around the world to the live events they love. As the world’s largest ticket marketplace and the leading global provider of enterprise tools and services for the live entertainment business, we are uniquely positioned to successfully deliver on that vision. We do it all with an intense passion for Live and an inspiring and diverse culture driven by accessible leaders, attentive managers, and enthusiastic teams. If you’re passionate about live entertainment like we are, and you want to work at a company dedicated to helping millions of fans experience it, we want to hear from you. Our work is guided by our values: Reliability - We understand that fans and clients rely on us to power their live event experiences, and we rely on each other to make it happen. Teamwork - We believe individual achievement pales in comparison to the level of success that can be achieved by a team Integrity - We are committed to the highest moral and ethical standards on behalf of the countless partners and stakeholders we represent Belonging - We are committed to building a culture in which all people can be their authentic selves, have an equal voice and opportunities to thrive EQUAL OPPORTUNITIES We are passionate and committed to our people and go beyond the rhetoric of diversity and inclusion. You will be working in an inclusive environment and be encouraged to bring your whole self to work. We will do all that we can to help you successfully balance your work and homelife. As a growing business we will encourage you to develop your professional and personal aspirations, enjoy new experiences, and learn from the talented people you will be working with. It's talent that matters to us and we encourage applications from people irrespective of their gender, race, sexual orientation, religion, age, disability status or caring responsibilities. #LI-REMOTE Live Nation Entertainment will never request payment or equipment purchases as part of the hiring process. Recruiters will only contact candidates from official Live Nation or affiliated brand email domains. Recognized for seven years as a Great Place to Work® and named one of Fortune’s World’s Most Admired Companies, Live Nation Entertainment is the world’s leading live entertainment company comprised of global market leaders: Ticketmaster, Live Nation Concerts, and Live Nation Media & Sponsorship. Our world-class teams specialize in all aspects of the live entertainment industry, from ground-breaking innovations in ticketing, global venue development and operations, concert promotion and production, sales and brand partnerships, and unparalleled artist management supported by professionals in all facets of corporate operations. We believe in taking care of the countless employees helping artists bring live music to fans all around the world. Our many unique benefit programs are designed to help our teams live life to the fullest including generous vacation, healthcare, retirement benefits, student loan repayment, tuition reimbursement, six months of paid caregiver leave for new parents including fostering and perks like Roadie Babies helping new parents care for their babies on work trips. And of course, access to free live events through our exclusive employee ticketing program. There is no bigger stage for your career. See what your future looks like at Live Nation Entertainment.