T Online Tools
Home / Blog / What is an SSL Certificate? How to Check Website Security Online

What is an SSL Certificate? How to Check Website Security Online

sslcertificatesecuritycheckerhttps

What is an SSL Certificate?

An SSL certificate authenticates a website’s identity and enables HTTPS encryption. When valid, your browser shows a padlock icon. Certificates are issued by Certificate Authorities like Let’s Encrypt, DigiCert, and Cloudflare.

Why SSL Matters

Without encryption, data on public Wi-Fi or shared networks is visible to anyone. SSL protects login pages, payment forms, and API calls. Google also uses HTTPS as a ranking signal — sites with valid certificates rank higher.

How to Check SSL

Our SSL Certificate Checker shows:

Common SSL Issues

Expired Certificate: Browsers show a “Not Secure” warning. Most certificates last 90 days to 2 years.

Domain Mismatch: The www and non-www versions need separate certificates.

Mixed Content: HTTPS page loading HTTP resources triggers browser warnings.

Use the SSL Checker to test any domain before deploying your own site.

← Back to Blog