While the HLAPI is designed to minimize boilerplate code, the Low-Level API (LLAPI) is designed to permit maximum flexibility. In general, using the LLAPI involves creating UnityWebRequests then creating appropriate DownloadHandlers or UploadHandlersand attaching them to your UnityWebRequests.
This section details the options available in the Low-Level API and the scenarios they are intended to address:
Note that the HLAPI and LLAPI are not mutually exclusive. You can always customize UnityWebRequest objects created via the HLAPI if you need to tweak a common scenario.
For full details on each of the objects described in this section, please refer to the Unity Scripting API.