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 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.

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.

What You Will Be Doing:

• Identify and act on production problems without being prompted.
• 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.
• 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.
• Drive observability improvements – ensuring services are instrumented for monitoring, alerting, and rapid incident response.
• Apply AI and machine learning tools to improve developer productivity, automate operational tasks, and enhance system capabilities.

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.
• Proven experience writing production code and building high-traffic systems at scale.
• Expertise in Java (17+); and the JVM, with strong command of JVM internals, garbage collection behavior, and performance tuning under load.
• 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.
• Strong command of gRPC (including streaming RPC) and binary serialization formats such as FlatBuffers, Avro, or Protobuf.
• Familiarity with Data-Oriented Design (DoD).
• 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.
• Hands-on experience with AWS (EKS) and cloud-native operations.
• 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.
• Experience designing for high availability – mult-region active-active/active-passive architectures, failover strategies, disaster recovery.
• Proficiency with AI/ML tools and techniques.
• Familiarity with observability tooling: Grafana, Splunk, Prometheus, OpenTracing, or equivalent.
• Strong understanding of security best practices – OAuth/OIDC, input validation, secrets management.

You (Behavioural Skills):

• Systems Thinking: Understands distributed systems as a set of tradeoffs.
• Technical Vision: Anticipates platform challenges and designs systems that scale ahead of demand.
• Ownership: Takes end-to-end responsibility for system health, performance, and reliability.
• Influence Without Authority: Drives architectural decisions and engineering standards through collaboration.
• Communication: Explains complex technical trade-offs clearly to both engineering peers and non-technical stakeholders.
• Continuous Improvement: Identifies opportunities to modernize, simplify, and strengthen systems.

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.