How Can i Connect Unity to Postgres Database

There may be assets on the Unity Asset Store to let you integrate some flavor of this DB. I have used ones to integrate SQLite and they worked quite well.

Otherwise if it is a database on a remote server, it’s like any other network resource: get it working from the PC first, then bring it up in Unity.

Networking, UnityWebRequest, WWW, Postman, curl, WebAPI, etc:

And setting up a proxy can be very helpful too, in order to compare traffic: