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The Box API supports two distinct methods of file upload. The supports files up to 50 MB and sends all the binary data to the Box API in one request. The support files from 20 MB. Upload the file in parts so you can catch errors and retry each part. When you upload a new version of a large file, you can also from the previous version.
To upload files to the Archive folder, first enable the (GCM) scope in the Developer Console.

Quick example

Upload a file to the root folder:

Upload limits

Upload limits depend on the authenticated user’s account type. See the .

Preflight check

The preflight check API enables you to verify that Box accepts a file before you upload any bytes. You can use it for new files and for new versions of existing files.

Learn more about preflight checks

Upload domain

Uploads to Box use a different domain (upload.box.com) than regular API calls. Keep this in mind when you write your own upload code. The Box SDKs choose the right domain for each API call.
Last modified on November 12, 2026