Free tool · Domain & site research
SSL certificate checker
Enter a domain to check its SSL certificate: who issued it, when it expires, how many days are left and whether the chain is valid. Catch expiries before they break your site.
What gets checked
- Days until expiry, with a warning when automated renewal looks stuck
- Hostname coverage, including wildcards and the www version
- The full chain: missing intermediates, self-signed and untrusted roots
- TLS version, the http:// to https:// redirect and HSTS
How it works
Three steps, no signup.
Enter a domain
Type the https domain you want to check.
Run the check
Lynx connects over TLS and reads the live certificate.
Review expiry and chain
See the issuer, valid-from and valid-to dates, days remaining and chain status.
FAQ
SSL Certificate Checker questions.
Why does SSL matter for SEO?
HTTPS has been a Google ranking signal since 2014, and browsers mark non-HTTPS pages as not secure, which scares off visitors. An expired certificate breaks the site entirely until it is renewed.
How often should I renew my certificate?
Public certificates issued since March 15, 2026 last at most 200 days, dropping to 100 days in 2027 and 47 days in 2029. Automate renewal (Let's Encrypt and most hosts do it for you) and check the days-remaining value here.
What is a certificate chain?
Your certificate is signed by an intermediate, which is signed by a trusted root. If an intermediate is missing, some clients show errors even though the certificate itself is valid. The checker reports chain issues.
Is the check safe?
Yes. The tool only opens a standard TLS connection to the domain you enter on the public web. It validates the hostname and refuses private or internal addresses.
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