SSL Checker
Enter a domain to see its certificate's issuer, validity dates, and whether it's currently trusted.
Overview
This tool connects directly to a domain on port 443 and inspects the certificate the server presents during the TLS handshake — the same certificate a browser would see. It reports the issuer, subject, validity window, and fingerprint, and flags whether the certificate is currently expired, self-signed, or otherwise fails standard trust validation.
Because the check happens server-side against the live certificate, it reflects exactly what's deployed right now — useful for confirming a renewal actually took effect or diagnosing why visitors might be seeing a browser warning.
Examples & Sample Data
A valid certificate
example.com
Valid until: Jan 2027
How It Works
- Enter a domain name, e.g. example.com.
- Complete the verification check if shown.
- Click Check to connect on port 443 and inspect the certificate.
- Review the issuer, validity dates, and trust status returned.
Common Use Cases
Confirming a certificate renewal
Verify a newly renewed certificate is actually being served before an old one expires.
Diagnosing a browser security warning
Check whether a certificate is expired, self-signed, or mismatched with the domain.
Tips & Best Practices
- A certificate can be technically valid but still untrusted by browsers if it's self-signed or issued by a CA not in the standard trust store — this tool reports both the certificate's own dates and whether it passes trust validation.
- Some servers present a different certificate depending on the requested hostname (SNI) — this tool sends the domain you enter as the SNI hostname, matching what a real browser visit would see.
Frequently Asked Questions
No. Each check connects fresh (or reuses a short-lived cached result) and nothing about the certificate is retained beyond that cache window.
A certificate can fail trust validation for several reasons: it's expired, self-signed, issued for a different hostname, or issued by a certificate authority not in the standard trust store. The tool reports the specific reason where available.
No, this tool always checks the standard HTTPS port (443).
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