Principal Software Development Engineer

Expedia Group•Seattle, WA

About The Position

Expedia Group brands power global travel for everyone, everywhere. We design cutting-edge tech to make travel smoother and more memorable, and we create groundbreaking solutions for our partners. Our diverse, vibrant, and welcoming community is essential in driving our success. Why Join Us? To shape the future of travel, people must come first. Guided by our Values and Leadership Agreements, we foster an open culture where everyone belongs, differences are celebrated and know that when one of us wins, we all win. We provide a full benefits package, including exciting travel perks, generous time-off, parental leave, a flexible work model (with some pretty cool offices), and career development resources, all to fuel our employees' passion for travel and ensure a rewarding career journey. We’re building a more open world. Join us. Introduction to the Team: Our Technology Team partners with teams across Expedia Group to create innovative products, services, and tools to deliver high-quality experiences for travelers, partners, and our employees. A singular technology platform powered by data and machine learning provides secure, differentiated, and personalized experiences that drive loyalty and traveler satisfaction. At Expedia Group Fraud & Risk (EFR), we are the guardians of marketplace trust. We protect EG from financial loss and brand damage, securing every channel for our customers, partners, suppliers, and employees. Our world class engineering and machine learning turn massive, noisy signals into real time decisions that minimize risk while keeping traveler friction low. What makes this work unique: in travel, risk doesn’t stop at checkout, it spans the entire journey. The global ecosystem is vast and fragmented, control points are scarce, and every leg introduces new unknowns. Our mission is bold: deliver a fully trusted journey from purchase to safe return home. That’s hard and exactly why science and technology matter most. If you’re energized by complex, high impact problems with no obvious answers, and want to shape the future of risk with AI on a global scale, join us. Let’s redefine how the world travels, safely, confidently, and at speed. Lead the architecture and delivery of real-time, AI-powered fraud and abuse defenses on a global scale. You will design cloud-native decisioning and automated remediation systems, simplify our platform, and align cross-functional teams to measurable outcomes.

Requirements

10+ years of software engineering, including 4+ years leading architecture for real-time, high-scale systems
Proven experience building and operating fraud/risk systems in production (e.g., booking, payments/chargebacks, ATO, content/supplier integrity), with measurable impact on losses, false positives, and manual effort
Production ML experience (supervised/anomaly detection, feature pipelines, online inference, monitoring/retraining); ability to ship with DS/ML partners
Cloud-native engineering at scale (AWS, GCP, or Azure): event-driven services, data/stream processing, observability, cost and reliability best practices
Strong coding skills in one or more of Java/Scala/Go/Python; microservices, APIs, and infrastructure-as-code
Security, privacy, and regulatory fundamentals for sensitive data and risk decisioning
Experience with executive communication: can brief executives, translate strategy into actionable engineering plans, and align teams

Nice To Haves

LLM/agentic techniques applied to fraud (e.g., investigation assist, pattern discovery, automated playbooks) and retrieval over enterprise data
Graph/sequence modeling or entity resolution at scale; device and behavioral signals
Track record reducing manual operations via automation and platform simplification
Hands-on with experimentation platforms and real-time rules/model simulation/back testing
Deep cloud cost/performance tuning and capacity planning
Marketplace, travel, or e-commerce experience

Responsibilities

Own end-to-end architecture for low-latency risk decisioning (signals + rules + models) and automated remediation
Build, deploy, and operate ML in production; partner closely with DS/ML on features, experimentation, and monitoring
Simplify and modernize the platform (streaming/data pipelines, microservices, CI/CD, configuration-driven controls) to speed safe iteration
Drive build-vs-buy evaluations and benchmark vendors against in-house solutions for performance, cost, and risk posture
Establish clear SLOs, observability, and safety/rollback mechanisms; ensure security, privacy, and compliance are built in
Mentor senior engineers and align Product, Ops, Security, and Compliance on roadmap and outcomes
Communicate clearly with executives and engineering: distill strategy, make tradeoffs explicit, and document decisions.

Benefits

full benefits package, including exciting travel perks, generous time-off, parental leave, a flexible work model (with some pretty cool offices), and career development resources
medical/dental/vision
paid time off
Employee Assistance Program
wellness & travel reimbursement
travel discounts
International Airlines Travel Agent (IATAN) membership

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