HTTP vs HTTPS

Plaintext vs encrypted web traffic

HTTP and HTTPS are protocols for transferring data on the web. HTTP sends data in plaintext, meaning anyone on the network can read it. HTTPS adds TLS encryption to protect the data in transit, making it the mandatory standard for modern websites.

HTTP

HTTP (HyperText Transfer Protocol) is the foundation of data communication on the web, originally defined by Tim Berners-Lee in 1991. It's a request-response protocol where browsers send requests (GET, POST, etc.) and servers return responses (HTML, JSON, images). HTTP transmits data in plaintext — every byte of the request and response is visible to anyone who can intercept the network traffic (ISPs, Wi-Fi operators, attackers). HTTP uses port 80 by default. While HTTP is still technically functional, modern browsers flag HTTP sites as 'Not Secure' and many web features (geolocation, service workers, HTTP/2) are restricted to HTTPS only.

HTTPS

HTTPS (HyperText Transfer Protocol Secure) is HTTP with a TLS (Transport Layer Security) encryption layer. Before any HTTP data is exchanged, the client and server perform a TLS handshake: the server presents a certificate proving its identity, they agree on encryption parameters, and a shared secret is established. All subsequent HTTP traffic is encrypted, ensuring confidentiality (no eavesdropping), integrity (no tampering), and authentication (you're talking to the real server, not an impersonator). HTTPS uses port 443 by default. Thanks to Let's Encrypt (free certificates since 2015), HTTPS adoption has gone from roughly 40% to over 95% of web traffic.

Key Differences

- **Encryption**: HTTP transmits plaintext. HTTPS encrypts all data using TLS, making it unreadable to interceptors. - **Authentication**: HTTP provides no server verification. HTTPS uses certificates to prove the server's identity, preventing man-in-the-middle attacks. - **Port**: HTTP uses port 80. HTTPS uses port 443. - **Performance**: HTTPS adds a small TLS handshake overhead on the first connection, but HTTP/2 (HTTPS-only) is actually faster than HTTP/1.1 for most workloads. - **SEO**: Google ranks HTTPS sites higher. HTTP sites are penalized in search results. - **Browser treatment**: Modern browsers show a padlock for HTTPS and a 'Not Secure' warning for HTTP.

When to Use Each

**Always use HTTPS.** There is no legitimate reason to use HTTP for any production website in 2026. Even for internal tools, static blogs, or hobby projects, Let's Encrypt provides free certificates with automated renewal. HTTP should only exist as a redirect to HTTPS. **The only exceptions** are local development (localhost), isolated internal networks with no internet exposure, and legacy embedded devices that cannot support TLS — and even these are shrinking.

Analogy

**HTTP** is like sending a postcard through the mail — anyone who handles it (the postal workers, your neighbors) can read the message written on the back. **HTTPS** is like sending a sealed, tamper-evident envelope — the contents are hidden from everyone except the intended recipient, and they can tell if someone tried to open it along the way.