PEM Certificate Decoder Online Free — View SSL/TLS Certificate Details

Free online PEM certificate decoder. View X.509 certificate details including subject, issuer, validity dates, SANs, and key info. Decode SSL/TLS certificates instantly.

PEM Certificate

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How to Use

Paste your PEM-formatted certificate (including BEGIN/END lines)
View the decoded certificate details instantly
Check the validity dates, subject, and issuer information
Verify Subject Alternative Names (SANs) for your domains

Common Use Cases

Verifying SSL certificate details before installation
Checking certificate expiration dates
Debugging TLS handshake and certificate chain issues
Inspecting certificate SANs for multi-domain coverage

Frequently Asked Questions

What information can I see from a PEM certificate?

You can see the subject (domain name), issuer (CA), validity dates, serial number, signature algorithm, public key type and size, and extensions like SANs and key usage.

Is it safe to paste my certificate here?

Yes. All decoding happens locally in your browser. Your certificate data is never sent to any server. Note: never paste private keys in any online tool.

What is the difference between PEM and DER format?

PEM is Base64-encoded text with header/footer lines, readable in any text editor. DER is the raw binary format. This tool only handles PEM format.