How does Scikit-Learn's Pipeline ensure consistent training and inference behavior?

Pipeline ensures the same sequence of transformations is applied during training and inference.

A Scikit-Learn Pipeline chains multiple steps such that each transformer is fit only on training data and reused unchanged during inference. This guarantees identical preprocessing logic in both phases, eliminating inconsistencies caused by manual preprocessing. Internally, each step is stored and executed sequentially, and only the final estimator produces predictions.