Feature logging is a technique used to generate historically accurate training data for real-time machine learning systems by fetching new feature values online at inference time and logging them offline for later use. This approach eliminates the need for complicated time-travel queries and joins logic, making it easier to synthesize accurate training sets. Feature logging also provides additional benefits such as auditing and explainability of models, custom analysis, and data quality monitoring. Tecton, a platform that enables real-time machine learning, has built-in feature logging capabilities that can be enabled with a single parameter, allowing users to log requests and access the logged dataset for model training or analysis.