Glossary
SSL certificate
An SSL certificate (more accurately TLS certificate) is the cryptographic credential that lets a website serve traffic over HTTPS instead of unencrypted HTTP.
SSL/TLS certificates encrypt traffic between the browser and the server, protecting data in transit. Browsers display the padlock icon next to the URL when a valid certificate is in use. The cryptographic guarantee is real — well-implemented HTTPS prevents the most common network-level attacks (eavesdropping, request tampering, session hijacking).
Modern certificates are typically issued for free by Let's Encrypt or ZeroSSL and auto-renewed every 90 days. Most managed hosting platforms (Vercel, Netlify, Cloudflare, Website Killer) handle issuance and renewal automatically — you point your domain at the host, the host provisions a certificate via ACME protocol on first request.
The technical distinction: SSL (Secure Sockets Layer) is the old name; TLS (Transport Layer Security) is the current protocol. TLS 1.3 (the standard in 2026) is faster and more secure than TLS 1.2 — handshake completes in one round-trip, weak ciphers removed. Most modern stacks default to TLS 1.3 with TLS 1.2 fallback for older clients.
Sites without HTTPS are flagged 'Not Secure' by Chrome, Firefox, and Safari — and Google ranks HTTPS sites higher than HTTP equivalents (a confirmed ranking signal since 2014). Beyond ranking, HTTPS is also a prerequisite for many modern browser features (service workers, HTTP/2, geolocation), so the cost of staying on HTTP is no longer 'just SEO'.
Certificate types: DV (Domain Validation, fastest to issue, suitable for most sites), OV (Organization Validation, requires verifying the business), EV (Extended Validation, used to show the green address bar but most browsers retired that UI in 2019). For 99% of sites, free DV certificates from Let's Encrypt are the right answer.
Example
Pointing your custom domain at Website Killer's nameservers triggers automatic SSL issuance via Let's Encrypt within minutes — no manual cert work, no payment, no renewal calendar. The padlock appears within minutes and renewal happens silently every 60 days.