Live SSL Checker

Enter a domain to inspect its certificate details directly on this page.

Certificate information will appear here after you run a check.

What this tool does

This SSL checker inspects the live SSL certificate presented by any domain and gives you an instant SSL health check: certificate validity, expiry date, issuer such as Let's Encrypt, negotiated TLS version, and an easy-to-read security grade. Use it as an SSL certificate checker, SSL expiry checker, or general TLS checker whenever you need to confirm a website's HTTPS security posture.

Understanding SSL security

What does an SSL checker actually check?

An SSL checker connects to a server over HTTPS, retrieves the SSL certificate it presents, and reports the details that matter for certificate validity: who issued it, when it was issued, when it expires, and which TLS certificate protocol version secured the connection. This SSL scan is the same basic process browsers use to decide whether to show a padlock or a security warning.

SSL certificate vs. TLS certificate

In everyday use, 'SSL certificate' and 'TLS certificate' refer to the same thing — TLS is the modern successor to the original SSL protocol, but the certificate that identifies your domain and encrypts traffic is still commonly called an SSL certificate. A TLS checker like this one reports the actual TLS version in use (for example TLS 1.2 or TLS 1.3) alongside standard certificate details.

Why SSL certificate expiry matters

Certificate expiry is one of the most common causes of sudden HTTPS outages. When SSL validation fails because a certificate has expired, browsers block the page with a hard warning and most traffic simply bounces. Running a routine SSL expiry checker or certificate expiry check against production domains catches this before customers ever see an error.

Use cases

  • Verify certificate expiration before it causes an outage
  • Review issuer and certificate chain quality
  • Validate HTTPS deployment quality after a renewal
  • Confirm which TLS version a server actually negotiates
  • Run an SSL health check across a portfolio of domains
  • Double-check a Let's Encrypt renewal completed successfully

Key features

Feature
Instant SSL certificate checker for any public domain
Feature
Certificate Status badge — Valid or Expired at a glance
Feature
Valid From and Valid Until dates in human-readable format
Feature
Days Remaining countdown, highlighted when expiry is near
Feature
Issuer detection, including Let's Encrypt and other CAs
Feature
SSL/TLS Version reporting for accurate TLS checking
Feature
Simple Excellent / Good / Warning security grade

How it works

FluxRadar opens a direct TLS connection to the target domain on port 443, inspects the server certificate and negotiated protocol, and presents the most relevant security information — status, issuer, validity window, TLS version, and a simple grade — for quick assessment.

Step-by-step guide

  1. Enter the domain — Type the domain you want to check (for example example.com) into the SSL checker box above — no https:// prefix needed.
  2. Run the SSL scan — Click Check SSL to trigger a live TLS handshake and certificate inspection against the domain's server on port 443.
  3. Review certificate validity — Check the Certificate Status badge along with the Valid From and Valid Until dates to confirm the SSL certificate is currently valid.
  4. Check days remaining — Look at the Days Remaining field — it's highlighted in orange or red once a certificate is inside its 30-day expiry window.
  5. Confirm issuer and TLS version — Verify the certificate was issued by a trusted certificate authority such as Let's Encrypt, and confirm the SSL/TLS version meets your security requirements.

Benefits

Benefit
Supports secure deployment reviews
Benefit
Helps prevent certificate-related outages
Benefit
Improves trust and operational visibility
Benefit
Makes SSL monitoring easy without a full security scanner
Benefit
Gives a plain-language SSL status instead of raw certificate dumps

Common errors and fixes

Error Likely fix
SSL check failed: [Errno -2] Name or service not known The domain doesn't resolve. Double-check the spelling or confirm the domain has an active DNS record with a DNS lookup first.
Certificate Status shows Expired The SSL certificate is past its expiry date. Renew the certificate with your certificate authority or hosting provider immediately to restore HTTPS security.
Connection timed out The server may not be listening on port 443, could be blocked by a firewall, or might be down. Confirm the site is reachable over HTTPS in a browser.
Security Grade shows Warning despite a valid certificate This usually means the certificate is inside its 30-day expiry window or the server is negotiating an older TLS version rather than TLS 1.2 or 1.3.

Best practices

  • Run an SSL expiry checker on all production domains on a recurring schedule, not just after deployment
  • Automate certificate renewal wherever possible to avoid manual SSL certificate checker reminders
  • Confirm the TLS version in use meets your compliance requirements — prefer TLS 1.2 or newer
  • Check SSL status immediately after any DNS, CDN, or load balancer change
  • Keep issuer information handy so you know who to contact if renewal fails

SSL security grade reference

Grade What it means Typical cause
Excellent Valid certificate with healthy expiry and TLS 1.3 Modern, well-maintained HTTPS deployment
Good Valid certificate with healthy expiry on TLS 1.2 Solid setup, could modernize to TLS 1.3
Warning Expired, expiring within 30 days, or an older TLS version Needs renewal or a TLS/protocol upgrade soon

Examples

Examples include github.com, letsencrypt.org, and your own production domain.

Documentation

The SSL checker inspects the certificate presented by the target host and reports the key security details.

Frequently asked questions

  • What does SSL checking reveal? It reveals certificate validity, issuer, expiry date, TLS version, and protocol support — everything you need for a quick SSL health check.
  • Why is SSL health important? It protects user trust and prevents browser errors and outages caused by an expired or misconfigured SSL certificate.
  • Is this SSL checker the same as an SSL certificate checker? Yes — SSL checker, SSL certificate checker, and TLS checker all describe the same type of tool: one that inspects a live certificate and reports its status.
  • How do I know if my SSL certificate is about to expire? Run the SSL expiry checker above; the Days Remaining field turns orange or red once your certificate is within 30 days of expiring.
  • Does this tool check the full certificate chain? It inspects the leaf certificate presented by the server, including issuer details, which is enough to catch the most common certificate chain and issuer problems.
  • What TLS versions does the SSL/TLS Version field report? It reports the actual protocol negotiated during the handshake, such as TLS 1.2 or TLS 1.3, so you can confirm outdated protocols aren't still in use.
  • Is there an SSL checker API? This page exposes the SSL checker through a simple web form; for programmatic or automated SSL monitoring, treat the same POST endpoint as an SSL checker API integration point.
  • Does the tool work with Let's Encrypt certificates? Yes — Let's Encrypt and other public certificate authorities are detected and shown in the Issuer field like any other SSL certificate.

Conclusion

A quick SSL health check today can prevent an embarrassing HTTPS outage tomorrow. Use this SSL checker as a routine SSL validation step after every certificate renewal, DNS change, or new deployment, and rely on the Days Remaining warning to stay ahead of certificate expiry instead of reacting to it.