In this role as a Senior Software Engineer, you will sit at the intersection of core backend engineering and applied machine learning. This is a hybrid role for a builder who can not only write production-grade code but also actively design and train intelligent systems. You will identify opportunities to apply intelligence by training your own lightweight models and heuristics to solve immediate product needs. Beyond your own modeling work, you will partner closely with Machine Learning Engineers to operationalize their research and deploy complex models at scale. You will architect the full lifecycle from feature selection and model integration to building the services and data pipelines that run them in production. Whether you are developing a custom re-ranking algorithm or optimizing inference latency for a deep learning model, you will own the end-to-end technical execution where systems meet AI. You will join the Search and Personalization team, the central engine that powers discovery across the entire Instacart marketplace. We own the search experience end-to-end, from the moment a user types a query to the final ranking of results. Beyond search, we drive the personalization intelligence that underpins systems across the entire company, ensuring every customer sees the most relevant products and recommendations. We function like a high-velocity startup within a well-established organization, combining massive scale with the agility to experiment and innovate. Join us to build the adaptive, intelligent core of Instacart that transforms a simple grocery run into a personalized shopping journey