.key

What is a .key file?

KEY is Apple's presentation format — known for beautiful templates and smooth animations, but limited to the Apple ecosystem.

Safe format
Type Document
By Apple Inc.
MIME application/x-iwork-keynote-sffkey

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What is it

Keynote is Apple's answer to PowerPoint, and .key is its native format. The presentations look gorgeous — Apple's design sensibility shows in the templates, transitions, and typography. Steve Jobs used Keynote for every Apple keynote (the name isn't a coincidence), and it remains the presentation tool of choice for designers and anyone who values visual polish over feature density.

The format stores slides as a ZIP archive containing Protocol Buffer data, preview images, and embedded media. Keynote supports animations, builds, cinematic transitions, and precise typographic control that PowerPoint approximates but doesn't match. The tradeoff: the animations and visual refinements only work in Keynote.

For sharing with non-Apple users, export to PPTX (File → Export To → PowerPoint) or PDF. The PPTX conversion preserves slide content and basic animations but loses Keynote-specific transitions and effects. PDF preserves the exact visual appearance but obviously loses all animation. When in doubt, present from a Mac with Keynote — no conversion preserves the full experience.

Technical details
Full Name
Apple Keynote Presentation
MIME Type
application/x-iwork-keynote-sffkey
Developer
Apple Inc.
Magic Bytes
50 4B 03 04
Safety
.key is a known, safe format. Presentation document. No executable content.
What opens it
Apple Keynote
FREE Mac / iPad / iPhone
iCloud.com
FREE Web
FAQ
How do I open a Keynote file on Windows?
iCloud.com opens Keynote files in any browser with an Apple ID. Alternatively, ask the sender to export as PPTX. Google Slides can import PPTX but not KEY directly.
Can I convert KEY to PowerPoint?
Yes. In Keynote: File → Export To → PowerPoint. Basic slides convert well. Keynote-specific transitions, Magic Move animations, and some design elements may be lost or simplified.
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