The SolarWinds Platform (a.k.a. the Legacy Orion Platform) is a unified suite of network and system management products. This platform is installed on one or more servers within your organization. IT professionals in your organization interact with the platform primarily through the environment's website, which provides a single pane of glass for monitoring your IT infrastructure.
The SolarWinds Information Service (SWIS) is a data access layer for the SolarWinds platform. It has its own SQL-like language called SolarWinds Query Language (SWQL). SWIS provides a kind of application programming interface (API) for the platform.