Postman API workspaces are the construct surrounding collections, APIs, mock servers, environments, monitors, and other aspects of producing and consuming APIs. Workspaces can be kept private, made available only to partners, as well as published publicly to engage with users via the Postman API Network.
Workspaces can be thought of as a repository, but instead of code, it is for APIs, the API lifecycle, governance, and the automation and orchestration involved with API operations. Workspaces are discoverable, possess role-based access control (RBAC), and have an API themselves for automating API operations. In my opinion, there should always be a workspace at the center of each API, no matter what it is doing as part of applications, integrations, or wherever else you are building.