HTTP
HTTP (HyperText Transfer Protocol) is an application-layer protocol that defines how messages are formatted and transmitted between web browsers (clients) and web servers. It operates as a request-response protocol: a client sends an HTTP request (e.g., GET, POST, PUT, DELETE) and the server returns an HTTP response with a status code and the requested resource. HTTPS is the secure version of HTTP, adding TLS encryption to protect data in transit.
Common HTTP Status Codes
| Code | Category | Meaning | Example Use |
|---|---|---|---|
| 200 | Success | OK | Page loaded successfully |
| 301 | Redirection | Moved Permanently | URL has changed |
| 400 | Client Error | Bad Request | Malformed request syntax |
| 401 | Client Error | Unauthorised | Login required |
| 404 | Client Error | Not Found | Page does not exist |
| 500 | Server Error | Internal Server Error | Server-side failure |
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Related Terms
TCP/IP Protocol
TCP/IP (Transmission Control Protocol/Internet Protocol) is the foundational suite of communication protocols used to interconnect network devices on the internet and most private networks. TCP handles reliable, ordered delivery of data by breaking messages into packets, acknowledging receipt, and retransmitting lost segments, while IP handles addressing and routing each packet to its destination. Together they form the backbone of modern digital communication, enabling everything from web browsing to email.
TLS/SSL
TLS (Transport Layer Security) and its predecessor SSL (Secure Sockets Layer) are cryptographic protocols designed to provide secure communication over a computer network, most commonly the internet. TLS establishes an encrypted channel between two parties through a handshake process that authenticates the server (and optionally the client) using digital certificates, negotiates encryption algorithms, and exchanges session keys via public key cryptography. It is the security layer behind HTTPS, securing web browsing, email, messaging, and VoIP communications.
DNS (Domain Name System)
The Domain Name System (DNS) is a hierarchical, distributed naming system that translates human-readable domain names (such as www.google.com) into numerical IP addresses (such as 142.250.195.68) that computers use to communicate. Often described as the "phone book of the internet," DNS makes it possible for users to access websites using memorable names instead of numeric addresses. DNS queries are typically resolved through a chain of DNS servers including recursive resolvers, root servers, TLD servers, and authoritative name servers.
HTTP was invented by Tim Berners-Lee at CERN in 1989 as part of the World Wide Web project. "HyperText" derives from Greek hyper (over, beyond) + English text, coined by Ted Nelson in the 1960s to describe non-linear linked documents. "Transfer Protocol" is straightforward English for a set of rules governing data movement.