Locations: London, Madrid, Poland, Prague, Valencia, Warsaw.Groupon is a marketplace where customers discover new experiences and services every day and local businesses thrive.To date we have worked with over a million merchant partners worldwide, connecting over 16 million customers with deals across various categories.In a world often dominated by e-commerce giants, we stand out as one of the few platforms uniquely committed to helping local businesses succeed on a performance basis.Groupon is on a radical journey to transform our business with relentless pursuit of results.Even with thousands of employees spread across multiple continents, we still maintain a culture that inspires innovation, rewards risk-taking and celebrates success.The impact here can be immediate due to our scale and the speed of our transformation.We're a "best of both worlds" kind of company – big enough for resources and scale, yet small enough that a single person has a surprising amount of autonomy and can make a meaningful impact.About the RoleJoin the CoreApps Platform team, the foundational engineering group at Groupon responsible for the general commerce engine.Our platform handles every customer interaction and transaction worldwide.This is a high-impact, senior-level Individual Contributor (IC) role with a dual mandate: ensuring KTLO stability at massive scale and accelerating a major platform modernization effort using an AI-first approach.You will own mission-critical services that handle 100,000+ Requests Per Minute (RPM) and champion the shift from legacy Java/Ruby systems to a cutting-edge TypeScript/Node.js microservices architecture, leveraging state-of-the-art AI coding tools to achieve unprecedented speed and quality.Key ResponsibilitiesDeliver complex technical initiatives independently within high-availability, mission-critical systems.Lead technical reviews and contribute to architectural decisions, specifically driving TypeScript/Node.js migrations.Champion AI-assist