The 3xx class of status codes represents redirection responses defined in RFC 9110. Each code serves a specific purpose: 300 Multiple Choices offers multiple resource representations, 301 Moved Permanently signals permanent URL changes with SEO implications, 302 Found provides temporary redirection (historically misused, leading to 303 and 307), 303 See Other redirects POST results to GET, 304 Not Modified enables conditional caching, 307 Temporary Redirect preserves methods, and 308 Permanent Redirect combines 301’s permanence with 307’s method preservation. Implementation requires understanding caching behaviors (301s may be cached indefinitely), SEO impacts (redirect chains dilute link equity), and security considerations (open redirect vulnerabilities). Modern web development heavily relies on these codes for domain migrations, HTTPS enforcement, URL canonicalization, and API versioning.