301 is a status code indicating that a resource has permanently moved. When visitors access the old address, they are automatically taken to the new address, and search engines will also update their records accordingly, transferring the access signals of the original address to the new address.
Typical applicable scenarios
- Website redesign: when the page structure or URL rules are adjusted, the old address needs to point to the new address
- Domain change: after the new domain is enabled, allow visits and indexing of the old domain to transition smoothly
- Address normalization: when multiple forms point to the same page, unify them into one standard address
- Correcting incorrect addresses: point incorrectly written links to the correct page
The criterion is whether this change will be retained in the long term. If it is only a temporary adjustment, a status code indicating a temporary move should be used; otherwise, search engines may abandon the original address too early.
How to set it up
There are mainly two types of setup methods: adding redirect rules in the server configuration file, which is suitable for batch and rule-based address migration; and returning the corresponding status code in the program and specifying the target address, which is suitable for redirects related to business logic.
When the migration scale is large, it is recommended to first verify the rules in a test environment, confirm there are no conflicts, and then apply them to the production site.
Notes
Avoid chained redirects. Redirecting from the old address to an intermediate address and then to the final address prolongs visitor waiting time and also reduces crawling efficiency. Ideally, it should be done in one step.
Update internal links at the same time. Redirects address external and historical links, while links in site navigation and articles should be changed directly to the new address without relying on redirects.
Do not rely on redirects for the long term. A large number of legacy redirects increases maintenance complexity. When conditions permit, they should be cleaned up, keeping only the necessary ones.
Continue monitoring after migration. Use the site's traffic data and error reports from search platforms to confirm whether the old address is still being accessed and whether any redirect failures exist, and correct problems promptly when found.