Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →

menu_book Course Curriculum (HTTP and Web Protocols) expand_more

Request Anatomy

GET request POST request Request target Host header User-Agent Accept header Content-Type header Authorization header

Response Anatomy

200 OK 201 Created 204 No Content 301 redirect 304 Not Modified 400 Bad Request 401 Unauthorized 404 Not Found

Methods & Semantics

PUT PATCH DELETE HEAD OPTIONS Safe methods Idempotent methods Conditional requests

Caching

Cache-Control max-age no-store ETag If-None-Match Last-Modified If-Modified-Since Vary Shared cache concept

Cookies & Security

Set-Cookie Secure cookie HttpOnly cookie SameSite cookie CORS preflight Content-Security-Policy Strict-Transport-Security CSRF token transport

Modern Transport

HTTP/2 multiplexing HTTP/2 header compression concept HTTP/3 over QUIC concept Content-Encoding gzip Transfer-Encoding chunked Range requests Server-Sent Events WebSocket upgrade

HTTP and Web Protocols / Caching

Last-Modified

Learn Last-Modified in HTTP and Web Protocols with a dedicated explanation, a concept-specific example, a production caution, and a mastery check.

12 min read • Intermediate

http-and-web-protocols-029.http

http

HTTP/1.1 200 OK
Last-Modified: Tue, 29 Sep 2026 03:00:00 GMT
Content-Type: text/html

What to watch

Content source & attribution

Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Last-Modified Mastery Check →

If-Modified-Since