What Is SSL Certificate?

An SSL certificate (technically TLS certificate, though "SSL" remains the common term) is a digital certificate that serves two purposes: it authenticates your website's identity, confirming to visitors that they're connected to the real version of your site and not an impersonator, and it enables HTTPS encryption, which protects data transmitted between your visitors' browsers and your server from interception.

When a website has a valid SSL certificate, browsers display a padlock icon in the address bar and the URL begins with "https://" instead of "http://". Websites without SSL certificates are flagged by modern browsers with "Not Secure" warnings that deter visitors and damage trust. Google also uses HTTPS as a ranking signal — all else being equal, HTTPS sites rank higher than HTTP sites. For these reasons, SSL certificates are no longer optional for any business website.

SSL certificates are issued by Certificate Authorities (CAs) after verifying the domain owner's identity. They come in several types: Domain Validation (DV) certificates verify domain ownership only and can be obtained in minutes — Let's Encrypt provides these for free. Organization Validation (OV) certificates verify the organization behind the domain. Extended Validation (EV) certificates involve the most thorough vetting. For most business websites, a standard DV certificate provides adequate security — the encryption strength is identical regardless of validation level.