A redirect is the mechanism that powers URL shorteners, CMS moves, marketing campaigns, and authentication handoffs. When the server receives a request for `/old-path`, it returns a status in the 3xx family along with a `Location` header naming the target. Compliant browsers immediately issue a new request to that target, usually preserving the HTTP method on 307 and 308 responses and downgrading to GET on 301, 302, and 303 responses. Redirects carry semantic meaning that search engines and caches respect: 301 signals a permanent move and consolidates PageRank; 302 and 307 mark temporary moves and preserve the original indexing; 308 is the permanent equivalent of 307. Chains of redirects (A → B → C) multiply the round-trip cost and can confuse crawlers — best practice is to keep chains at most one hop. At the URL-shortener level the redirect is also the attachment point for analytics: the redirect handler increments counters, classifies the country/device, and then issues the `Location` response, all ideally within tens of milliseconds so the user experiences the short link as a near-instant jump.