ShareGate Migrate is a client-side only application that uses available APIs (CSOM, REST, GRAPH, SOAP, etc.) and other methods to recreate your source at the destination. The app does not interact directly with your database(s).
For more information about SharePoint migrations and prerequisites, see Walkthrough - Copy structure and content or Walkthrough - Copy content only.
Diagram
Requests are sent to the Microsoft APIs to get information from the source.
ShareGate Migrate sends requests to your Active Directory through SharePoint's people picker service to resolve your users for permissions and metadata values, like created by and modified by.
SharePoint returns the data from the calls sent in point (1) to the app.
Requests are sent to get information from the destination and to build structure elements from the source like sites, lists, and columns.
In Normal mode to a Microsoft 365 destination or any speed mode to an on premises version of SharePoint, list items and documents are sent directly to the destination instead of the Azure storage described at point (6).ShareGate Migrate receives information from the requests sent at point (4).
When you migrate to a Microsoft 365 destination in Insane mode, ShareGate Migrate uses the SharePoint online migration API. Your list items and documents are packaged and sent to an Azure storage (included with your tenant by default) with a manifest package. Some requests are sent to Azure to get a status update for the import to Microsoft 365 process that occurs at point (7).
Microsoft 365 imports the packages from the Azure Storage to your SharePoint destination.
Azure returns status updates about the packages being imported to Microsoft 365.
Note: The data that transitions through ShareGate Migrate will be encrypted when you connect to a SharePoint site that uses HTTPS. At point (6), Microsoft encrypts your data at rest with AES CBC 256 Standard encryption. For more information see Encryption and security.