A redirect chain sends a browser or crawler through several redirects, A to B to C to D, before finally reaching the intended page, rather than the original URL redirecting straight to the destination. The sequence may happen too quickly for a visitor to notice, but it creates real friction for crawlers, and real, measurable delay even for visitors on slower connections.
Google has said it follows up to roughly 5 nested redirect hops before giving up on a chain, though staying well under that isn't just about avoiding the hard limit: each additional hop in a chain adds latency, and evidence suggests each redirect also dilutes some amount of the link value the original URL carried, on top of simply wasting crawl budget that could go toward pages actually worth indexing. Chains build up gradually, usually through several separate migrations or restructures over time (URL A gets redirected to B during one project, then B gets redirected to C during a later one) rather than through any single mistake, which is why they're worth auditing periodically: find every redirect currently pointing at another redirect, and repoint each one directly at the final live destination instead.
