Key Skills

Job Description

We're excited to announce an opening in our Experimentation Core team for a Senior Software Engineer I. This is a great opportunity to shape the platform that powers experimentation across Booking.com. WHY JOIN US? Join a high-performing team that's collaborative, diverse, and genuinely motivated. Your ideas matter here and so does the impact you'll make. Team Scope And Impact Our team builds and maintains the core experimentation platform - the backbone of data-driven decision-making at Booking.com. Think real-time metrics, experiment lifecycle management, and statistical frameworks used by thousands of engineers and data scientists daily. Innovative Solutions: We work at the intersection of engineering and data science, building systems that are deeply statistical and mathematical in nature. Our stack includes Java, AWS, and modern tooling — and we actively leverage AI to accelerate our workflows. WHO ARE WE LOOKING FOR? A senior engineer who builds and owns complex, high-scale systems end-to-end. You bring excellent coding skills, strong system design judgment, and thrive in ambiguity. You'll elevate the team through high engineering standards. Must-haves Top-tier coding, testing, and production ownership skills Strong experience with asynchronous messaging and queuing systems (e.g., Kafka, SQS) End-to-end service ownership mindset (monitoring, SLIs/SLOs) Deep, hands-on Java experience, Solid understanding of security best practices as a baseline Strong communication skills - you'll work with many stakeholders across engineering, data science, and product Experience collaborating with data science teams or working on DS-adjacent products Big Plus Affinity for statistical/mathematical concepts - you don't need a Data Science background, but curiosity and patience for statistically complex products is essential AWS, GraphQL, Perl, Flink Experience with JavaScript Above all, we value camaraderie, authenticity, curiosity, autonomy, and proactivity.

Core Responsibilities

Build and maintain Booking.com’s core experimentation platform, including real-time metrics, experiment lifecycle management, and statistical frameworks. Own complex, high-scale systems end to end, with responsibility for engineering quality, production operations, and collaboration across engineering, data science, and product.

Requirements

Requires strong Java expertise, excellent coding and testing skills, experience with asynchronous messaging and queuing systems, and end-to-end service ownership including monitoring and SLIs/SLOs. Candidates should have sound system design judgment, security knowledge, strong communication skills, and experience collaborating with data science teams or working on data-science-adjacent products.