If you’re unfamiliar, foreign data wrappers, or FDW, allow you to connect from within Postgres to a remote system. Then you can query them from directly within Postgres. While there is an official Postgres FDW that ships with Postgres itself, that allows you to connect from one Postgres DB to another, there’s also a broad community of others.
Source: A tour of Postgres’ Foreign Data Wrappers Craig Kerstiens