What is a PEM file?
A .PEM file (Privacy-Enhanced Mail) is a Base64-encoded text file used to store cryptographic keys, certificates, and certificate requests. The format is a widespread internet standard heavily utilized by cryptographic software like OpenSSL. .PEM files always feature distinct headers and footers, such as `-----BEGIN CERTIFICATE-----`, which enclose the structured, encoded data. A single .PEM file might contain a public key, a private key, an X.509 certificate, or an entire certificate trust chain like the Mozilla CA root certificate bundle.
How to open PEM files?
Because .PEM files use standard text encoding, you can open them in any text editor. You can use Notepad++ on Windows, Apple TextEdit on macOS, or Vim on Linux. However, reading the Base64 text does not reveal the decoded certificate details, such as the issuer or the expiration date. To view the parsed contents, administrators rely on command-line utilities. For example, running `openssl x509 -in file.pem -text -noout` with OpenSSL displays the certificate details in a readable layout.
Best practices and troubleshooting
.PEM files are versatile container files. This means a single file can hold multiple items, like a server certificate and a private key together. If you experience an error when importing a .PEM file, verify that it contains the correct components for your specific system. Always treat .PEM files with caution. If the file contains a private key (`-----BEGIN PRIVATE KEY-----`), it is highly sensitive. Never share a private .PEM file publicly or upload it to untrusted servers.
Software and tools
viewer.online/pem can analyze .PEM files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available. Since .PEM has multiple possible meanings and contents, viewer.online/pem helps identify the actual format of your file quickly and safely.
Summary
In summary, viewer.online/pem is useful for identifying, inspecting, and understanding .PEM files without installing software or dealing with compatibility problems. If you need to convert your file for a specific server or application, we recommend converting to sensible target formats like .DER, .PFX, or .CRT on convert.guru.