The feature store is a data architecture concept used to accelerate data science experimentation and harden production ML deployments. Nate Buesgens and Bryan Christian describe a practical approach to building a feature store on Delta Lake at a large financial organization. This implementation has reduced feature engineering “wrangling” time by 75% and has increased the rate of production model delivery by 15x. The approach described focuses on practicality. It is informed by innovative approaches such as Feast, but our primary goal is evolutionary extensions of existing patterns that can be applied to any Delta Lake architecture. Key Takeaways: – Understand the key use cases that motivate the feature store from both a data science and engineering perspective. – Consider edge cases where there may be opportunities for simplification such as “online” predictions. – Review a typical logical data model for a feature store and how that can be applied to your business domain. – Consider options for physical storage of the feature store in the Delta Lake. – Understand common access patterns including metadata-based feature discovery.