Online Tool Store
SSL Checker
Look up a domain's SSL/TLS certificate issuer, validity dates, protocol version, and covered hostnames in a clean, readable summary.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown - live checks for other domains need a server-side TLS handshake, which this preview doesn't connect to.
Valid certificate
Issued to
Issuer
Valid period
Protocol
Subject alternative names
How an SSL checker works
- Enter a domain name to check.
- A checker opens a TLS connection to that domain and reads the certificate presented during the handshake.
- It reports the issuer, validity window, negotiated protocol, and covered hostnames from that certificate.
Why this needs a server component
Opening a raw TLS socket to an arbitrary host is not something browser JavaScript can do - it is a lower-level network operation reserved for actual HTTP requests. A production version of this tool would perform the handshake from a small backend service and return the parsed certificate to the page.
FAQ
What does an SSL checker actually verify?
It connects to a domain over HTTPS, retrieves its TLS certificate, and reports the issuer, validity dates, protocol version, and the domains the certificate covers (subject alternative names).
Why does this only show a live result for the example domain?
Browsers cannot open a raw TLS connection to an arbitrary domain from JavaScript - that requires a server making the connection on your behalf. This page shows the interface with a real example; connecting it to a live checker is a backend integration outside the scope of this preview.
What happens if a certificate has expired?
A production checker would flag the certificate as expired or invalid and most browsers would show visitors a security warning before letting them continue to the site.
What is a subject alternative name (SAN)?
A SAN is an additional hostname a single certificate is valid for, such as covering both example.com and www.example.com with one certificate.
How we compare
| Feature | Online Tool Store | SSL Labs | Browser padlock icon |
|---|---|---|---|
| Clean, readable summary layout | ✓ | Detailed but dense | Minimal detail |
| No sign-up or ads | ✓ | ✓ | ✓ |
| Works for any site you're not currently visiting | ✓ | ✓ | ✗ |
For a quick, focused summary without a deep technical report, SSL Checker gets straight to the key facts.