SSL certificate and HTTPS checker

Check that your certificate is valid and not about to expire, that http leads to https, and find every image or script that still loads insecurely and breaks the padlock.

Free, no account. Up to 25 checks a day per visitor.

What it checks

  • Served over HTTPSWithout TLS, everything a visitor types can be read on the way, and browsers mark the site "Not secure".
  • TLS certificateAn expired or mismatched certificate turns the site into a full-page browser warning.
  • HTTP Strict Transport SecurityTells returning browsers to never try http first, closing the window where a connection can be hijacked.
  • Mixed contentAn https page loading http scripts or styles loses its padlock, and browsers block the insecure parts.
  • Cookie flagsA session cookie without Secure and HttpOnly can be stolen by a script or over an open network.
  • Forms submit over HTTPSA form posting to plain http sends what was typed — passwords, card numbers — in the clear.

Questions

Why does the browser say "Not secure" when I have a certificate?

Usually mixed content: the page is https but loads an image, script or form over http. This tool lists each one.

What happens when the certificate expires?

Browsers show a full-page warning instead of your site, and most visitors leave. Free certificates last 90 days, so automatic renewal matters.

Is a free certificate as secure as a paid one?

For encryption, yes. Let's Encrypt certificates are trusted by every browser; paid ones add support and warranty, not stronger encryption.

We only read what a public visitor could. Nothing is submitted to your site and no vulnerability is exploited — findings are what your site shows, not what we tried.

More free tools

Or run all fifty checks at once