Principal Software Engineer I - Marketplace Data & AI

About Us: At , data drives our decisions. Technology is at our core and innovation is everywhere. But our company is more than datasets, lines of code or A/B tests. We’re the thrill of the first night in a new place. The excitement of the following morning. The friends you make. The journeys you take. The sights you see. And the food you sample.

Through our products, partners and people, we can empower everyone to experience the world.

Marketplace Data & AI exists to turn 's scale into a competitive advantage. We build the intelligence products and data platforms that power how travelers discover, plan, and book – from the ranking and recommendation engines that shape every search result, to the traveller context models that make personalization possible across the entire Marketplace. We drive decisions through experimentation, building a culture of testing and measurement that extends beyond Marketplace to the wider company.

We sit at the intersection of data engineering, machine learning, product thinking, and data science, and we're accountable for outcomes, not just capabilities.

Within Marketplace Data & AI, this role spans four connected product areas.

combines the AI Application Platform (AIAP) with the AI applications (GenAI and more) built on top of it. AIAP is a product built on top of 's core Platform layer, purpose-designed to solve the engineering capabilities that Customer AI specifically requires. It is not a generic shared platform. It has a defined consumer and a clear product mandate. Sitting above it are the traveler-facing AI applications that AIAP enables, where we drive business impact and customer outcomes.

is the intelligence and ML layer that powers how  ranks, recommends, and optimizes benefits. This covers ranking models, recommendation engines, and benefits optimization; the proprietary signal work that drives measurable commercial and traveler outcomes.

is both a platform and a culture. We build the platform and engineering foundations that enable rigorous, data-driven decision making across Marketplace and the wider company, and this role helps set the standard for how experimentation is designed, run, and learned from.

is our investment on building a unified understanding of the traveler – their context, preferences, intent, and behavior across the  ecosystem. It is the intelligence layer that makes personalization meaningful, and that feeds the AI products and experiences built across all other areas.

Across all four areas, we hold two things simultaneously: the discipline of a product organization – owners, roadmaps, accountability for outcomes, and the ambition to scale what we build beyond Marketplace to the whole company.

Principal Engineers are the technical leaders involved in key business initiatives. They own the technical strategy and co-create and drive the tactical plan to achieve these goals. They are role models, mentors, and strategists who oversee and execute technical tasks with excellence.

As a Principal Software Engineer, you will be responsible for setting the technical vision for the AI Application Platform and the intelligence products it enables, and defining the fundamental guidelines for architectural and technical design and the SDLC. These guidelines should employ specific reusable patterns and recommendations that can be applied to major product increments across 's intelligence capabilities.

This role requires deep domain knowledge in data and AI engineering — you understand how intelligence products are built end-to-end, from data pipelines and feature stores through to model serving, experimentation, and outcome measurement.

You will partner with product, data science, machine learning, and platform engineering crafts to achieve results across the intelligence product portfolio. You will establish a coherent intelligence engineering strategy by collaborating with other engineering and architecture owners, aligning on clear system…