Is the SSL Certificate Parser free?

Yes, it's completely free. No registration, no login. All parsing happens locally in your browser.

Is my certificate data uploaded to a server?

No. This tool uses client-side parsing — your certificate content never leaves your browser. You can disconnect from the internet and the tool still works.

What certificate formats are supported?

PEM format X.509 certificates (starting with -----BEGIN CERTIFICATE-----). Also supports Base64-encoded DER certificates. PKCS#12 (.pfx/.p12) and JKS formats are NOT supported — convert them to PEM with openssl first.

Can it detect expired certificates?

Yes. The tool parses the certificate's validity period (Not Before and Not After) and compares with current time. It automatically flags expired, not-yet-valid, and soon-to-expire (within 30 days) certificates with visual warnings.

SSL Certificate Parser - Free Online X.509 Decoder | PEM Parse

📘 How to Use

Paste a PEM format X.509 certificate and click Parse to view all details. Export certs from your browser or use the openssl command.

Get a certificate: Browser: click lock icon → Connection secure → Certificate → Details → Export. Or command line: openssl s_client -connect example.com:443 </dev/null | openssl x509 -outform PEM

All parsing happens locally in your browser — certificate data is never uploaded.

❓ FAQ

How do I get a website's SSL certificate?

Three ways: 1) Browser: click lock icon → Connection secure → Certificate → Details → Export → Base64-encoded X.509 (.CER), open with text editor. 2) openssl command (see above). 3) SSL testing tools like SSL Labs.

Is my certificate data safe?

Yes. This tool parses certificates locally in your browser using JavaScript's ASN.1 parser via Web Crypto API. Certificate content is never sent to any server. SSL certificates are public information, but your usage remains private.

What information does it extract?

Subject (CN/Organization), Issuer, Validity period (Not Before/Not After), Days remaining, SAN (Subject Alternative Name) domains, Public key algorithm and size, Signature algorithm, Serial number. Automatically flags expired or soon-to-expire certificates.

Why did parsing fail?

Ensure you paste PEM format (starts with -----BEGIN CERTIFICATE-----). Common issues: PKCS#12 (.pfx/.p12) not supported — convert first. Certificate chain with multiple certs — paste only the first (server) certificate. Extra spaces or line breaks — clean up the paste.

🔒 SSL Certificate Parser

📜 Paste PEM Certificate

📋 Certificate Details