On May 5th 2015, Microsoft had released new API for SharePoint Online Migration to fast the migration process from SharePoint On-premises to SharePoint Online.
To use this API, all you need to have is AZURE Storage Account for storing your migration packages temporarily.
- Create Package using API
- Upload the package to azure blob storage
- Use CSOM call to start the migration process, Azure queue gets real time updates
- Once complete the logs in the package get updated
One thing you need to remember while using API is that you need have to structure ready at the destination. Current version of API migrate only data it does not migrate the structure like site creation, list creation, content type creation etc. And also this API does not support workflow associations.
Currently four third-party tools are supported this API. This API gels very well with the third-party migration tool. The third-party migration tool will create the structure required at the destination and utilizes this API for migration of data, in this way it will be faster your migrations.
Alternate approach is create custom tool in association with the SharePoint Online Migration API, for this type of scenario will have wait until Microsoft releases the original version. Currently it is in beta program.
For more details, please refer to the nice blog.
Ignite Video about SharePoint Online Migration API