301 Redirect

301 Redirect in plain English

When a server returns HTTP status 301 with a Location header pointing at a new URL, every browser and crawler treats the move as permanent. Bookmarks should update, search engines should re-index under the new URL, and link equity from any inbound link to the old URL transfers to the new destination (though Google has stated this transfer is now lossless, in practice some sites see slight ranking dips post-migration).

The contrast is 302 (temporary) — the original URL stays the primary, equity doesn't transfer, search engines keep the old URL indexed. Use 302 only for genuinely temporary moves (A/B tests, geo-localization on a single canonical URL). Every other case where a URL changes for good wants 301.

Standard ecommerce uses: product URL changes ("old-product-name" → "new-product-name"), category restructures ("/blog/post-slug" → "/blog/2026/post-slug"), HTTP→HTTPS migrations, www-vs-non-www consolidation, removing trailing slashes, replacing /products/?id=123 with /products/widget-blue, and any URL cleanup after a CMS migration.

The most common 301 mistake is chained redirects: A→B→C→D where each hop is a separate 301. Each hop loses a small amount of equity and adds latency. Google says it follows up to ten hops but slows down crawling on long chains. Audit periodically with Screaming Frog and replace chains with direct A→D redirects.

Why 301 redirect matters for ecommerce

Every product URL change is a potential rankings disaster if not 301'd properly. A store that renames "running-shoes" to "athletic-footwear" without 301s loses every link, every social share, every Google-indexed URL pointing at the old slug — months of accumulated SEO value vaporized. The 301 keeps the equity flowing. For Shopify stores specifically, automatic redirects exist for URL handle changes, but they're capped at 100,000 redirects per store and don't handle category URL restructures. Maintain a deliberate redirect map alongside any URL change.