I was thinking about epub support, but apparently they do now but dropped mobi support. I haven’t used a Kindle in awhile so no idea if there are any caveats. Here’s the full list for anyone interested:

Send to Kindle for Web

Microsoft Word (.DOC, .DOCX)
HTML (.HTML, .HTM)
RTF (.RTF)
Text (.TXT)
JPEG (.JPEG, .JPG)
GIF (.GIF)
PNG (.PNG)
BMP (.BMP)
PDF (.PDF)
EPUB (.EPUB)

Send to Kindle from the Kindle App for iOS and Android Devices

PDF (.PDF)
Microsoft Word (.DOC, .DOCX)
HTML (.HTML, .HTM)
RTF (.RTF)
Text (.TXT)
Images (.JPG, .JPEG, .GIF, .PNG, .BMP)
EPUB (.EPUB)

Kindle Personal Documents Service

Microsoft Word (.DOC, .DOCX)
HTML (.HTML, .HTM)
RTF (.RTF)
Text (.TXT)
JPEG (.JPEG, .JPG)
GIF (.GIF)
PNG (.PNG)
BMP (.BMP)
PDF (.PDF)
EPUB (.EPUB)

Send to Kindle Desktop Applications

Microsoft Word (.DOC, .DOCX)
PDF (.PDF)
Text (.TXT)
Images (.JPG, .JPEG, .PNG, .BMP, .GIF)
RTF (.RTF)
HTML (.HTML, .HTM)
EPUB (.EPUB)

Yeah, you can sideload pirate ebooks onto a Kindle. There are some restrictions with file formats, most people use Calibre if they run into issues with them. For ebooks I just grab mine from libgen most of the time.

My coworkers were talking today about all the hoops they were going through with streaming to find the content they wanted and navigating the byzantine extra charges to share it with their family. If piracy wasn’t an option I still wouldn’t go through all that, it’s madness how much worse the paid service is to the high seas.