What is SSL/TLS Check?
Enter a domain and this tool shows you the most recent SSL/TLS certificate issued for it: who issued it (the certificate authority), its validity period and all the domains it covers, with a clear warning of how many days remain before it expires.
Since a Cloudflare Worker cannot open a raw TLS connection to read the live served certificate, the data comes from the public Certificate Transparency logs (crt.sh), where every issued certificate is published. It is a fast way to monitor your certificates' expiry or to inspect which certificates exist for a domain, without openssl commands.
Frequently asked questions
Is it free?
Yes, all NewKit tools are completely free.
How does it work without installing anything?
The tool runs on Cloudflare Workers at the edge: your browser makes a lightweight request to our server, which performs the network lookup and returns the result. There is nothing to configure.
Is there a usage limit?
To keep the service free and within Cloudflare's free tier, we apply a reasonable daily request limit. For normal use you will not notice it.