PEM Certificate Parser

What Can the PEM Certificate Parser Do?

The PEM Certificate Parser is a pure frontend online tool for parsing PEM-formatted X.509 certificates, private keys, and CSRs. Enter PEM content to view subject, issuer, validity period, serial number, SAN extensions, and more. Automatically checks certificate expiration. All parsing happens locally in the browser.

Core Features

• Certificate Parsing: Parse X.509 certificates showing subject, issuer, validity, serial number
• Validity Check: Automatic expiration detection with color-coded status
• SAN Extensions: Display all domains and IPs in Subject Alternative Name
• Private Key Detection: Identify RSA/EC private key type and key length
• File Drag & Drop: Drag .pem/.crt/.key files directly

How to Use

Step 1: Paste PEM content or drag a certificate file.

Step 2: Click "Parse".

Step 3: View parsed results including certificate details and validity status.

Step 4: Copy any information you need.

Use Cases

SSL Certificate Check

Ops teams quickly check SSL certificate validity, domain coverage, and issuer information.

Certificate Debugging

Developers verify certificate chains and SAN extensions when configuring HTTPS.

Security Audit

Security teams review key length, signature algorithm, and validity against security policies.

Certificate Renewal

Check current certificate details for accurate renewal before expiration.

Extended Knowledge

PEM (Privacy-Enhanced Mail) is the most common certificate storage format using Base64-encoded DER data between -----BEGIN ...----- and -----END ...----- markers. X.509 is the international standard for public key certificates, defining structure and content including version, serial number, signature algorithm, issuer, validity, subject, public key info, and extensions. SAN (Subject Alternative Name) allows one certificate to protect multiple domains and is standard for modern HTTPS certificates.

FAQ