OpenAnyFile
Works
Viewing, inspecting and verifying. You get the full text content with encoding detection. File details, exact byte size and the detected signature are always shown.
How to open a .key file
The short version: KEY is an Apple Keynote / Private Key from Apple / OpenSSL. The longer version — including the quirk that trips most people up — is below, along with a viewer that runs entirely on your own device.
What is a .key file?
Apple Keynote / Private Key is a text & markup format developed by Apple / OpenSSL, first appearing in 2003. It is normally produced by Apple Keynote, OpenSSL.
Two unrelated things share this extension: a Keynote ZIP package, or a PEM-encoded private key beginning '-----BEGIN'. Never share the second kind.
| Full name | Apple Keynote / Private Key |
|---|---|
| File category | Text & markup |
| MIME type | application/vnd.apple.keynote |
| Magic bytes (file signature) | 50 4B 03 04 or 2D 2D 2D 2D 2D |
| Developer | Apple / OpenSSL |
| Introduced | 2003 |
| Usually created by | Apple Keynote, OpenSSL |
| OpenAnyFile engine | plain text reader |
| Opens without upload | Yes — parsed locally in your browser |
Open a .key file in your browser
OpenAnyFile routes .key to its plain text reader, which displays the full text content with encoding detection.
- Open the OpenAnyFile opener in this browser — nothing to download or sign up for.
- Drag your .key file onto the drop zone, click to browse for it, or paste it with Ctrl+V.
- The extension is detected and the file is handed to the plain text reader.
- Your KEY opens on its own viewer page: the full text content with encoding detection.
- Use fullscreen for a closer look, or download the file back out unchanged. Nothing is transmitted anywhere — the parsing happens in your own browser process.
What you can and cannot do with it here
Does not work
Editing and re-saving. OpenAnyFile is a reader, not an editor — for changes you still need special software or an equivalent.
Is it safe to open a {E} file on a website?
It depends entirely on whether the website uploads it, and almost all of them do. That is a real problem when the text & markup file in question is a contract, a client deliverable or something under NDA. OpenAnyFile removes the question: the decoding happens inside your browser tab, so there is no transfer, no queue, no temporary storage and no retention window to read about in a privacy policy.
Frequently asked questions about KEY files
Can I open a .key file without installing special software?
Yes. OpenAnyFile's plain text reader runs in your browser, so you can read a KEY file with nothing installed. You get the full text content with encoding detection. For full editing you still need the original application — this is a viewer, not an editor.
How can I check a file really is a KEY file?
Look at the first bytes rather than the extension. A genuine KEY begins with 50 4B 03 04 or 2D 2D 2D 2D 2D. Opening the file in OpenAnyFile shows that signature in the file-details panel, so a file renamed to .key by mistake is easy to spot.
Is it safe to open a KEY file online?
With OpenAnyFile, yes, because nothing is uploaded. The file is read locally through your browser's File API and never leaves your device, so there is no server copy to leak, log or retain. That matters most for the kind of file people are least willing to hand to a random converter site.
What is a .key file, exactly?
Apple Keynote / Private Key — an application/vnd.apple.keynote format created by Apple / OpenSSL since 2003. Two unrelated things share this extension: a Keynote ZIP package, or a PEM-encoded private key beginning '-----BEGIN'. Never share the second kind.
Does the same viewer handle formats related to KEY?
Yes — the same engine also opens .dat, .srt, .cer, so you can compare related files without switching tools.
Related formats
These open with the same engine, so if you have one of these sitting next to your .key file, it will open too: