Certificate Details Viewer
Parse and inspect SSL/TLS certificates from PEM input. View subject, issuer, validity dates, SANs, key info, and extensions.
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How to Use This Tool
Paste a PEM-encoded X.509 certificate into the input field and click Parse. The tool decodes the certificate client-side and displays all key fields including subject, issuer, validity dates, Subject Alternative Names, public key details, and extensions.
Common Use Cases
- Inspecting SSL/TLS certificates before deploying to production
- Verifying certificate expiry dates and SANs during renewals
- Debugging certificate chain issues in web applications
- Auditing certificates for compliance with security policies
Frequently Asked Questions
What certificate formats are supported?
This tool supports PEM-encoded X.509 certificates — the format that starts with -----BEGIN CERTIFICATE-----. This is the most common format used by web servers, including certificates from Let's Encrypt, DigiCert, and other CAs.
Is my certificate data sent to a server?
No. All parsing happens entirely in your browser using JavaScript. Your certificate data never leaves your machine. This makes the tool safe to use with production certificates.
What information can I see?
You can view the subject (CN, O, OU, C), issuer, serial number, validity period (not before / not after), Subject Alternative Names (SANs), public key algorithm and size, signature algorithm, and key usage extensions.
How do I get a certificate in PEM format?
You can export a certificate from your browser (click the padlock → Certificate → Export), use OpenSSL (openssl s_client -connect example.com:443 </dev/null | openssl x509), or copy it from your server's certificate files (usually .crt or .pem files).