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 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 peakon-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 systemstradeoffs, 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 thatremainresilient 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 oftradeoffdecisions made under real constraints. Your value comes from understanding thosetradeoffsclearly 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.

• 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, orwork 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.

• Identifyandeliminatesingle points of failure, improving systemreliabilityand 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.

• Proven ability to reasonaboutdistributed systemstradeoffs- 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, withstrongcommand 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 Web Flux , 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,…