TLS Certificate Content Viewer
Inspect PEM certificate metadata locally (subject, issuer, validity, SAN, and fingerprints)
Paste a certificate block and click Analyze
Parses PEM certificate content client-side and extracts X.509 fields with no network calls.
About TLS Certificate Viewer
Inspect PEM-encoded TLS/SSL certificates to view subject, issuer, validity period, Subject Alternative Names (SANs), key usage, and SHA-256 fingerprints. TLS certificates are fundamental to HTTPS security, and developers frequently need to inspect them when debugging SSL errors, validating certificate chains, checking expiration dates, or verifying SANs match expected domains. This viewer parses X.509 certificates locally in your browser — your certificate data is never sent to a server.
How to Use TLS Certificate Viewer
- Paste a PEM-encoded certificate (starting with -----BEGIN CERTIFICATE-----) into the input field.
- View the parsed certificate details: subject, issuer, validity dates, SANs, and fingerprint.
- If multiple certificates are pasted, each one is parsed and displayed separately.
- Copy individual fields using the copy buttons.
TLS Certificate Viewer FAQ
What certificate details are shown?
The viewer displays subject (CN, O, OU), issuer, validity window (not before / not after), Subject Alternative Names, key usage, basic constraints, and SHA-256 fingerprint.
Can I inspect multiple PEM certificates at once?
Yes. If you paste a PEM file containing multiple CERTIFICATE blocks (e.g. a full chain), each certificate is parsed and displayed separately.
Can I check if a certificate is expired?
Yes. The validity dates (not before and not after) are displayed, so you can immediately see if the certificate is currently valid or has expired.
What are Subject Alternative Names (SANs)?
SANs list the domain names and IP addresses that a certificate is valid for. Modern browsers require the domain to appear in the SAN field, not just the Common Name.
Is my certificate data sent to a server?
No. All certificate parsing happens locally in your browser. Your PEM data never leaves your device.