The Box API supports two distinct methods of file upload. The direct file
upload API supports files up to 50MB in size and sends all the binary
data to the Box API in 1 API request.The chunked upload APIs support files from 20MB in size and allow an
application to upload the file in parts, allowing for more control to catch any
errors and retry parts individually.
To upload files to the Archive folder, you need to first enable the Global
Content Manager (GCM) scope in the Developer Console.
The Pre-flight check API allows an application to verify that a file will be
accepted by Box before it uploads any bytes. It can both be used for new files,
as well as uploading new versions of existing files.
Uploads to Box happen via a different domain (upload.box.com) than regular API
calls. This is something to keep in mind when writing your own upload code. All
the Box SDKs will take care of choosing the right domain for the right API call.