Expiry
Track the exact validity window.
SSL/TLS Certificate Checker
SSL/TLS Certificate Checker
Check certificate expiry, hostname coverage, trust chain and live TLS security settings.
Example: Accepts domains, HTTPS URLs and custom ports. Results are not stored as history.
SSL/TLS check result
No check started
Enter a domain or HTTPS website address, then click Check certificate.
SSL / TLS SECURITY
What is an SSL/TLS certificate check?
An SSL/TLS certificate authenticates a website and encrypts data between browsers and servers. A complete check goes beyond the padlock: it reviews hostname coverage, validity dates, certificate chain, public trust and the TLS parameters negotiated by the server.
This tool connects directly to the target server and reads its public certificate and handshake data, helping site owners catch configuration failures before visitors see browser warnings.
Trust chain
Review server and intermediate certificates.
TLS
Inspect the live protocol and cipher.
Why check SSL certificates regularly?
Certificate renewal, CDN migrations, load balancers and intermediate-CA updates can break a previously healthy HTTPS setup. Regular checks reduce the risk of outages, trust warnings and failed search-engine crawling.
Prevent expiry outages
See the exact expiry date and days remaining, and catch renewal or deployment failures early.
Verify hostname and trust
Confirm that the SAN covers the host and that the intermediate chain validates publicly.
Find outdated TLS settings
Review the negotiated protocol, cipher suite and public key strength against modern baselines.
How does the SSL checker work?
The server resolves the public address, sends the original hostname as SNI during a real TLS handshake, then analyzes the certificate and connection independently.
- 01
Validate the target
Normalize the host and port while blocking local, private and reserved network addresses.
- 02
Perform a TLS handshake
Connect to the public IP and retain the hostname as SNI to obtain the intended certificate.
- 03
Parse the chain
Read CN, SANs, issuer, validity, key, fingerprint and the available certificate chain.
- 04
Return repair actions
Flag expiry, hostname mismatch, trust, weak-key and obsolete-protocol problems.
How to read the SSL result
Fix expiry, hostname mismatch and trust failures first because they directly trigger browser warnings. Schedule soon-to-expire certificates, weak keys and old protocols for prompt maintenance.
Validity and hostname
The current time must fall within the certificate dates and the requested host must appear in its SAN list.
Trust chain
The server, intermediate and trusted root certificates must form a path browsers can validate.
Protocol and encryption
Modern sites should prefer TLS 1.3 with a securely configured TLS 1.2 fallback for older clients.
SSL/TLS certificate checker FAQ
How early should I renew a certificate?+
Confirm successful renewal at least 30 days before expiry. Monitor automated renewal too: successful issuance does not guarantee deployment to every CDN, proxy or origin.
Why does a browser warn when the certificate is still valid?+
Common causes include hostname mismatch, a missing intermediate, mixed page content, a different port, or different certificates on the CDN and origin.
What is a certificate chain?+
The chain links the server certificate through one or more intermediate CAs to a trusted root. A server normally sends its certificate and the required intermediates.
Is TLS 1.2 still secure?+
Properly configured TLS 1.2 remains a useful fallback, but enable TLS 1.3 first and disable TLS 1.0, TLS 1.1 and weak cipher suites.
Are check results stored?+
No. Results remain on the current page. The server uses only a short cache to reduce duplicate connections and creates no indexable history.
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