SSL Certificate Checker
Verify SSL/TLS certificate validity, expiration date, issuer, and protocol details.
What SSL Checker Checks
Instantly audit every critical aspect of a domain's SSL/TLS certificate.
Certificate Validity
Confirms whether the SSL certificate is currently valid and trusted by major browsers and operating systems.
Expiration Check
Shows the exact expiry date and the number of days remaining so you can renew before browsers show security warnings.
Issuer Details
Identifies the Certificate Authority (CA) that signed the certificate, such as Let's Encrypt, DigiCert, or Sectigo.
Protocol & Cipher
Reports the active TLS protocol version and cipher suite negotiated during the handshake for security auditing.
Subject Alt Names
Lists all domains and subdomains covered by the certificate, including wildcard entries like *.example.com.
Fingerprint Info
Displays the SHA-256 fingerprint and serial number so you can uniquely identify and verify the certificate.
How It Works
Three simple steps to check any domain's SSL certificate.
Enter Domain
Type the domain name you want to inspect — no need to include https:// or www. Just the bare domain is enough.
Check Certificate
Our server initiates a TLS handshake and retrieves the full certificate chain directly from the target server.
Review Details
View validity status, expiry countdown, issuer, protocol, cipher, SANs, and fingerprint all in one place.
TLS Protocol Versions
Understanding which TLS version your server uses matters for security and compatibility.
Related Tools
Other network and security tools you might find useful.
Frequently Asked Questions
Common questions about SSL certificates and TLS security.
Why does SSL matter for my website?
SSL/TLS encrypts data transmitted between your visitors' browsers and your server, preventing eavesdropping and man-in-the-middle attacks. Browsers mark sites without valid SSL as 'Not Secure', which damages user trust and can hurt search rankings. Google has used HTTPS as a ranking signal since 2014.
What happens when an SSL certificate expires?
When a certificate expires, all major browsers immediately display a full-page security warning that blocks visitors from accessing your site. This results in lost traffic, damaged reputation, and potential revenue loss. Most CAs send reminder emails at 30, 14, and 7 days before expiry — or you can use automated renewal tools like Certbot for Let's Encrypt certificates.
What is the difference between TLS 1.2 and TLS 1.3?
TLS 1.3 (released 2018) is faster and more secure than TLS 1.2. It removes weak cipher suites, reduces the handshake from two round-trips to one, and supports 0-RTT resumption. TLS 1.2 is still widely accepted and secure when configured correctly, but TLS 1.3 is the current best practice. TLS 1.0 and 1.1 are deprecated and should be disabled.
What are Subject Alternative Names (SANs)?
Subject Alternative Names (SANs) are additional domain names that a single certificate protects. For example, a certificate for example.com might also cover www.example.com, api.example.com, and *.example.com via a wildcard entry. Multi-domain (SAN) certificates are standard practice and are more efficient than purchasing separate certificates for each subdomain.