URL redirection

What it is

A redirect is a server response telling the client to request another address instead. The status code carries the meaning: 301 and 308 signal a permanent move, 302 and 307 signal a temporary one, and search engines treat them differently when deciding which URL to index. Redirects can be set at server level, in a CDN, or by application logic or meta refresh, though server-side status codes are the clearest signal.

Why it matters

When URLs change without redirects, existing links, bookmarks and indexed pages break, so accumulated authority and traffic are lost. Correct permanent redirects consolidate signals onto the surviving URL and preserve most of that equity. Redirects also remove duplicate variants such as HTTP versus HTTPS and trailing slash differences, which keeps crawl budget and indexing focused on canonical addresses.

How it works

Practitioners build a one-to-one mapping from old URLs to the closest matching new ones, avoiding blanket redirects to the homepage, then implement the rules server-side and test before launch. After going live, they crawl the old URL list to confirm each returns a single 301 to a live 200 page, fixing chains and loops that dilute signals and slow crawling. Server logs and Search Console reports are used to catch redirects missed in the mapping.

When it applies

Use redirects whenever a URL changes permanently, pages are merged or retired with an equivalent replacement, or a site moves domain, protocol or structure. Use temporary codes only for genuinely temporary situations such as short campaigns or maintenance pages.

Examples

• A publisher changes its URL structure and maps 12,000 old article URLs to their new paths with 301 redirects.
• An ecommerce site retires a discontinued product and redirects it to the parent category rather than a 404.
• A brand consolidates a microsite onto a subfolder of the main domain and redirects every old page to its closest equivalent.

How it is measured

• Share of old URLs returning a single 301 to a live 200 page
• Number of redirect chains, loops and redirects to 404 pages found in a crawl
• Recovery of organic clicks and impressions on migrated URLs versus the pre-migration baseline
• Crawl errors and soft 404 counts reported in Search Console after launch