SSL Certificate Decoder

Parse and inspect SSL certificate details from PEM format

Paste Certificate (PEM format)

Decoded Certificate

Subject

Issuer

Validity

Not Before

Not After

Key Information

Type

Size

Subject Alternative Names

No SANs

Fingerprints

Serial Number

SHA-256 Fingerprint

Error

About Certificate Decoder

Our free Certificate Decoder parses PEM-encoded SSL/TLS certificates and displays all fields in a human-readable format. Paste any certificate to instantly view its subject, issuer, validity period, key information, SANs, serial number, and SHA-256 fingerprint. Useful for debugging certificate issues and verifying certificate contents before deployment.

How to Use

1Paste your PEM-encoded certificate into the text area.
2Click "Decode Certificate" to parse and display all fields.
3Review the subject, issuer, validity, key info, SANs, and fingerprints.

Use Cases

•Decode and verify certificates received from a CA
•Inspect certificate details before installing on a server
•Verify SANs match your domain names
•Check certificate fingerprints for integrity verification
•Debug certificate chain and issuer information

Technical Details

Supported Formats

PEM (Base64-encoded text)
DER (Binary format)
PKCS#7 (Certificate chain)

Parsed Fields

Subject, Issuer, Validity dates
SANs, Serial number, Fingerprints

Tips & Best Practices

•Always verify the certificate's SANs match all domains you're securing
•Check the issuer to ensure the certificate was issued by a trusted CA
•Compare validity dates to ensure the certificate is currently active

Frequently Asked Questions

Yes, paste the DER-encoded certificate and our tool will convert and decode it automatically.

Subject Alternative Names allow a single certificate to secure multiple domains (e.g., example.com and www.example.com).

Ensure the certificate is properly PEM-encoded with BEGIN/END markers. Binary DER certificates need to be pasted as-is.

Video Tutorial

Video tutorial coming soon