Apple Keynote Presentation (.key)

The KEY file extension is commonly associated with Apple Keynote Presentation, a software developed by Apple for creating and playing back presentations. Keynote presentations are stored in the Mac OS X package format and can include slides with images, shapes, tables, text, notes, media files, and XML-related data.

Keynote is similar to Microsoft PowerPoint but is primarily intended for Mac users. When saved to iCloud, these files use the ".KEY-TEF" extension instead of ".KEY". Keynote is available on Mac and iOS devices as part of the iWork productivity suite.