SSL & Security

SSL Checker

Certificate Analysis

Check website SSL certificate

Enter a domain name and port to analyze the SSL certificate, test TLS security, check HSTS configuration, and verify CAA records.

Tool features

Comprehensive SSL certificate and security analysis with detailed recommendations
4 checks

Certificate Analysis

Comprehensive SSL certificate validation and chain analysis

Security Assessment

TLS version support, cipher analysis, and security features

DNS Security

CAA record verification and HSTS configuration check

SSL Status

Check SSL activation, TLS versions, expiry, and certificate chain

What is an SSL certificate & how it works

Trust, validity, and TLS configuration in one check

An SSL/TLS certificate is the credential a website presents so browsers can encrypt the connection and confirm they are really talking to the domain in the address bar. Checking it means validating three things at once: that the certificate is trusted (issued by a recognised authority and chained correctly), that it is still valid (not expired and covering the right hostname), and that the server negotiates a modern, secure TLS configuration.

This checker connects to the domain on the port you choose, completes the TLS handshake, and inspects the certificate chain, expiry window, subject alternative names, protocol versions, and related hardening signals such as HSTS and CAA records. It surfaces the exact problems a browser would flag — an expired cert, a name mismatch, an incomplete chain, or a weak protocol — so you can fix them before visitors see a warning.

Certificate chain
The path from your leaf certificate up through intermediates to a trusted root CA. A missing intermediate is the most common trust error.
SAN (Subject Alt Name)
The list of hostnames a certificate is valid for. The domain you visit must appear here or the browser rejects it.
TLS version
The protocol negotiated for the connection. TLS 1.2 and 1.3 are secure; 1.0 and 1.1 are deprecated and should be disabled.

How to use this tool

Analyze a site's SSL certificate in four steps
1
Enter a domain and port
Type the hostname (and port 443 for standard HTTPS, or a custom port for other services).
2
Run the SSL check
We complete a live TLS handshake and read the certificate the server actually presents.
3
Review the certificate and TLS config
Check the issuer, expiry, hostname coverage, chain completeness, and protocol versions.
4
Fix any warnings
Renew before expiry, install missing intermediates, or disable deprecated TLS versions.

Related tools

Keep debugging with tools from the same suite
5 tools
SSL Scanner
Advanced SSL/TLS security scanner with comprehensive vulnerability assessment and configuration analysis
SSL Expiration Checker
Check SSL certificate expiration dates and get alerts before certificates expire
Certificate Decoder
Decode and analyze SSL certificate contents, properties, and metadata in detail
TLS Checker
Check supported TLS versions and cipher suites on a server for security compliance
HSTS Checker
Check HTTP Strict Transport Security (HSTS) header configuration and preload status

Frequently asked questions

Common questions about SSL certificate checks
5 Q&A

Browsers show a full-page security warning and block the site until users click through. An expired cert breaks trust and hurts conversions — renew before the expiry date.

Your browser may have cached an intermediate certificate from another site. Other clients won't, so they see an incomplete chain. Install the full intermediate bundle on the server to fix it for everyone.

Enable TLS 1.2 and TLS 1.3 only. Disable SSL 3.0, TLS 1.0 and TLS 1.1 — they are deprecated and fail modern security requirements like PCI DSS.

TLS is the modern successor to SSL. The term 'SSL certificate' has stuck, but the actual protocol negotiated today is always TLS.

Yes. Enter the port your service listens on (for example 8443 or 993) and the checker will complete the handshake against that port.