SSL Certificate Checker

Check the TLS / SSL certificate of one or many hosts at once. Each host is looked up in the Certspotter certificate-transparency log, which reports the most recently issued non-revoked certificate — its expiry, issuer and validity window. It needs no proxy and no API key, so results come straight from your browser.

Checks run in your browser, but to look up certificate expiry the hosts you enter are sent to the Certspotter API. Nothing else leaves your device, and we do not store your lookups.

Host Issuer Valid from Expires Days left Status

How To Use

  1. Paste one host per line (e.g. example.com). Schemes, paths and ports are stripped automatically.
  2. Click Check SSL certificates. The most recently issued, non-revoked certificate per host is shown.
  3. Read the Days left and Status badges: Expiring soon = under 30 days, Expired = past expiry.

Usage Example

Input:

example.com
example.org

Example rows after a Certspotter check (dates vary by lookup):

Host          Issuer               Expires      Days left   Status
example.com   Sectigo RSA DV CA   2026-12-02   220         Valid
example.org   Let's Encrypt E5    2026-09-25   24          Expiring soon

Only non-revoked certificates are reported, using the most recently issued one per host.

Frequently Asked Questions

Why does it return a recently issued certificate?

Certspotter reads the certificate-transparency logs, which hold every certificate that has been issued for a host — including old ones that are already superseded. To best reflect what a site likely uses now, this tool picks the most recently issued non-revoked certificate (a renewal is issued right before it is deployed).

Is this a live check, or an approximation?

It is an approximation, not a live handshake. A CT log records that a certificate was issued, not that the server is already serving it. Renewals are usually issued shortly before they are switched on, so the most recently issued certificate is the closest guess to what a site runs today — but if a site has just renewed and not yet swapped it in, the result can differ by up to a few days from the certificate currently being served.

What do the status badges mean?

Valid = more than 30 days until expiry; Expiring soon = under 30 days; Expired = already past the expiry date; Error = the lookup failed (timeout, rate limit, or no non-revoked certificate found) — other hosts still complete.

Does this upload my hosts?

Yes — checking a certificate requires asking the Certspotter API for it, so the hosts you type are sent there. No server in this project stores your lookups, and nothing else leaves your browser.

Does it need a proxy or an API key?

No. Certspotter sends CORS headers and provides this lookup free without a key, so the browser can call it directly.