PDF to AZW3

The file is uploaded to our server because it's necessary to process it with Calibre, but it's deleted immediately after conversion.

Because Calibre can only generate AZW3, not the classic AZW format. Additionally, AZW3 is what current Kindle devices use.

Yes. Images from the PDF are embedded in the AZW file.

It works best with text-based PDFs. With scanned documents the result may be poor, since Calibre needs to be able to read the content.

Because generating a valid AZW3 requires Calibre, which can only run on a server, not directly in your browser.

Usually a few seconds, although it may vary depending on the PDF size and server load at that moment.