A 302 redirect is an HTTP status code indicating that a resource has been temporarily moved to a different URL. Unlike a 301, a 302 tells browsers and search engines that the original URL is still valid and should be used for future requests. The redirect is treated as a temporary detour rather than a permanent change.
In URL shortening, 302 redirects are commonly used because they allow the shortening service to maintain control over the redirect and accurately track every click. Since browsers do not cache 302 redirects as aggressively as 301s, each visit to the short URL passes through the shortening service's servers, enabling real-time analytics. Web analytics books on Amazon discuss tracking methodologies.
The SEO implications of 302 redirects differ from 301s. A 302 does not pass link equity to the destination URL, which means the short URL itself may accumulate ranking signals rather than the destination. For most URL shortening use cases, this distinction is irrelevant because short URLs are not intended to rank in search results.
Historically, there was confusion about the semantics of 302 redirects. The HTTP/1.0 specification defined 302 as a generic temporary redirect, but implementations varied. HTTP/1.1 introduced 303 and 307 to clarify the intended behavior, though 302 remains widely used. HTTP protocol books on Amazon explain the evolution.