301 redirect is a status HTTP code that signals permanent redirection of one URL to another. If users reach the original (non-existent) URL, the search engine will automatically redirect them to the new one.
If we decide to make any interventions on the site to existing URLs, we should remember to redirect them. If we change the URL or remove the page without turning it, users will be taken to a non-existent page with a 404 code. This will lead to a bad user experience, and search engines will exclude the page from their index. We may also lose the portfolio of backlinks and organic traffic that the original site has built up. And we don’t want that.
Permanent redirection (301 redirects) is most often used for:
- to change the URL,
- changing URL structures,
- site removal,
- web migration to a new domain,
- redirected from non-www to www version or vice versa,
- redirected from HTTP to the HTTPS version,
- merging of two (or more) domains.
- See also temporary 302 redirects.
We moved the blog established on the subdomain: https://blog.domainname.com to the subfolder: https://domainname.com/blog and set a permanent 301 redirect.
This tells the browser that we have permanently redirected the original page and do not want it to send users there. If, even after the redirection is set, the user reaches https://blog.domainname.com (e.g., clicks from a non-updated backlink), he ends up here: https://domainname.com/blog. All this can happen in a very short time, and the user does not even have to register the change.