SSL Certificate Checker — Free Online Tool
SSL Certificate Checker lets you inspect SSL certificates by domain lookup or PEM paste — no server-side processing, no installs.
Features
- Domain lookup — fetches certificate info via crt.sh certificate transparency logs
- PEM paste — parse any certificate with a built-in ASN.1 DER decoder
- Expiry status — days remaining with color-coded progress bar
- Self-signed detection — flags when CN matches issuer CN
- SANs display — all Subject Alternative Names with wildcard highlighting
- Certificate chain — shows end-entity and issuer/CA
- Full details — serial number, signature algorithm, key algorithm, key size
What Gets Checked
| Field | Info |
|---|---|
| Expiry | Days left, expired/warning/ok status |
| Common Name | Subject CN |
| Issuer | Certificate Authority |
| SANs | All covered domains (wildcards flagged) |
| Serial | Hex-encoded serial number |
| Algorithm | RSA/ECDSA with hash |
Try It
https://ssl-checker-abh.pages.dev
Part of the DevNest.io collection of free developer tools.
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