Also known as: .cer

Commonly opened with
  • OpenSSL
  • Windows Certificate Manager
  • Keychain Access (macOS)
Supported platforms
  • Windows
  • macOS
  • Linux
Editable?
Not really — it's a runnable or packaged format
Viewable without special tools?
Usually, yes
Commonly converted to
  • .pem
  • .pfx
Inherent format risk
Generally low risk
Safety guidance (not a guarantee)

Contains cryptographic key, certificate, or credential material. Handle private keys and credentials carefully, and never share them with anyone you don't fully trust.

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File extension lookup

No upload, no sign-up — everything is analyzed locally in your browser.

Frequently asked questions

What is a .crt file?

A public-key certificate file, typically used to verify identity for TLS/SSL connections or code signing.

Can I edit a .crt file?

Not directly as text — .crt is a runnable or packaged format, not one meant for manual editing.

Does having a .crt extension mean the file is safe?

No single extension can guarantee that. Contains cryptographic key, certificate, or credential material. Handle private keys and credentials carefully, and never share them with anyone you don't fully trust. Always consider where the file came from, not just its name.

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