Software Development Engineer III - Back End, GenAI Platform

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.

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.

Expedia Technology teams partner with our Product teams 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.

The Software Developer III role is part of the GenAI Platform team. The GenAI Platform team builds and operates Expedia Group’s shared generative AI platform – tooling, services, and guardrails – that enable product and ML teams to safely experiment with, deploy, and scale GenAI-powered experiences across our brands. You will design and deliver backend services powering AI capabilities across Expedia Group.

You’ll write production code, mentor junior engineers, and drive well-scoped projects from design through delivery. The role blends core software engineering fundamentals with hands-on work in the GenAI stack—RAG pipelines, vector stores, LLM integrations, and platform guardrails.

In this role, you will:

• Design, build, test, and operate Python- and FastAPI-based backend services and APIs that power GenAI Platform capabilities, including RAG Manager, RAG Data Plane, and vector store services.
• Implement sound system design (including low-level design), API design, and data modeling for backend services that are reliable, secure, and easy for internal customers to adopt.
• Integrate backend services with LLM providers, Elasticsearch-based vector stores, and Aurora Postgre
  
  SQL as part of Expedia Group’s RAG and GenAI platform stack, ensuring robust and observable data and inference flows.
• Contribute to and enhance platform guardrails and safety features such as authentication, API key management, workload-to-workload authorization, evaluation hooks, and monitoring to keep GenAI applications responsible and compliant.
• Safely integrate and operate AI/ML-enabled solutions, tools, and workflows that improve developer and traveler outcomes, including familiarity with AI-driven systems and applying foundational AI/ML concepts to real-world platform products.
• Own well-scoped projects end-to-end—from technical design and implementation through rollout, documentation, and post-launch improvements—while mentoring junior engineers and collaborating closely with staff/principal engineers, product managers, and applied scientists.

• Bachelor’s degree in Computer Science or a related technical field; or equivalent related professional experience.
• 5+ years of relevant professional experience.
• Proven experience building and operating backend APIs and services in a cloud environment, preferably AWS, including automated testing, CI/CD pipelines, monitoring, logging, and participation in on-call rotations.
• Strong proficiency in Python and experience with FastAPI or similar web frameworks, with solid understanding of software design principles, data structures, and design patterns.
• Hands-on experience with at least one data store technology (relational, No
  
  SQL, or search), with familiarity using systems like Postgre
  
  SQL or Elasticsearch to support service-level data modeling and persistence.

• Experience designing and operating internal platforms, shared services, or…