There are several ways by which you can ingest multiple assets in an automatic [or semi automatic] manner.
You can use the dropfolder mechanism, the bulk upload mechanism or utilise the upload APIs directly in your own code.
With the bulk upload mechanism, you can submit an XML or CSV with HTTP[s] URLs to the assets, while specifying the metadata. If you opt for that route, there’s no need for an SFTP server. Simply place all your media assets in the docroot or a web server and submit a bulk upload CSV/XML.
Sample CSV/XML files can be obtained from KMC->Upload->Download CSV/XML Samples.