HTTPS & SSL Checker — Free & Instant

About this tool. Confirms your site answers over HTTPS with a certificate our edge trusts, times the response, and reports the security headers that matter (HSTS and friends).

Ten signals decide whether your mail arrives. You just checked one.

A trusted certificate on the website says nothing about the mail. They are separate systems, and only one of them decides whether your invoices reach the inbox.

SPF, DKIM, DMARC, MX and blocklist status, graded A to F in one pass
Every problem written out in plain English, with the record to publish
Saved under Reports, so you can re-run it and see what changed
One domain watched against the blocklists daily

Run the full checkup free

No card, and nothing to cancel.

How to read your HTTPS results

We connect over HTTPS and report TLS reachability, redirects, and key security headers like HSTS.
A successful HTTPS response means the certificate is valid and trusted by our edge. Missing security headers are worth adding.

Common problems and how to fix them

HTTPS works but security headers are missing

Add HSTS, and consider a content security policy and other standard headers, to harden the site.

Certificate errors

Renew or reissue the certificate, and make sure the full chain is served, not just the leaf certificate.

HTTP Check TCP Port Test SMTP Test Latency Test Full email checkup

Common questions.

What does an HTTPS check verify?

That the site answers over TLS with a valid certificate, how it redirects, and which security headers it sends.

What is HSTS?

HTTP Strict Transport Security. A header that forces browsers to use HTTPS for your site, preventing downgrade attacks.