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SSL Certificate

TLS Certificate | HTTPS Certificate

Portrait of Lukas Horvath, co-founder of Roelu Studio
Lukas HorvathCo-founder

What is SSL Certificate?

An SSL certificate is a digital file installed on a web server that encrypts the connection between a visitor's browser and the site. It enables HTTPS — the protocol shown by the padlock icon in the address bar — and verifies that the visitor is connecting to the legitimate domain. Modern SSL certificates are technically TLS certificates, but the older SSL name has stuck across the industry.

Why it matters

An SSL certificate is no longer optional. Google flags sites without HTTPS as Not Secure in Chrome. Conversion rates on flagged sites collapse. Modern features — service workers, geolocation, payment APIs — refuse to run without it. Worse, anything submitted over plain HTTP, including passwords and credit card numbers, travels the wire in plain text for anyone on the network to read. The fix is free. Let's Encrypt issues certificates at no cost and most modern hosts install and renew them automatically. There is no excuse to ship a site without one in 2026.

How it works

You request a certificate from a Certificate Authority — Let's Encrypt is the most common free option — proving you control the domain by adding a DNS record or a file on the server. The CA issues the certificate, your host installs it, and traffic to the domain is now encrypted. Browsers verify the certificate against trusted root authorities every time someone visits. Modern hosts like Vercel, Cloudflare, and Netlify handle the whole flow invisibly — you point the domain at them and HTTPS is live in minutes. Certificates typically expire every ninety days, but renewal is automated and you never think about it.

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