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HTTP

Hypertext Transfer Protocol

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Application-layer protocol for transmitting hypermedia documents, such as HTML. Foundation of the World Wide Web.

Application LayerRFC 91101991IETF Standard

HTTP is the foundation of data communication on the Web, defining how clients (browsers, apps) request resources and servers respond. Standardized in RFC 9110, it operates over TCP (HTTP/1.1, HTTP/2) or QUIC (HTTP/3) and uses a request-response model with methods, headers, and status codes.

Key Characteristics

Request-Response

Client sends request, server returns response. Stateless by default.

Text-based (HTTP/1.x)

Human-readable headers and messages in HTTP/1.x. Binary framing in HTTP/2+.

Extensible

Headers, methods, and status codes can be extended without protocol changes.

Cacheable

Responses can be cached by intermediaries and clients for performance.

Message Format

Request
http
GET /api/users?limit=10 HTTP/1.1

Host: api.example.com

Accept: application/json

User-Agent: curl/8.4.0
Response
http
HTTP/1.1 200 OK

Date: Tue, 12 Dec 2023 10:00:00 GMT

Content-Type: text/html; charset=utf-8

Content-Length: 1234

[Response body]

Implementations

linuxbuilt-in
macosbuilt-in
windowsbuilt-in
freebsdbuilt-in
iosbuilt-in
androidbuilt-in