Feast, for the most part, is a feature store that serves up features to machine learning models for inference or training. PostgresML is closer to Big Query ML.

Feast, for the most part, is a feature store that serves up features to machine learning models for inference or training. PostgresML is closer to Big Query ML. They provide the framework to building, deployment, and inference of models from within the database - using extensions for PostgreSQL. This allows analysts and other users to build models off primarily tabular data without needing to figure out the whole deployment mess.