A forwarding notice for the web
If a shop moves a product page, a redirect sends people using the old URL to the new one. Their bookmarks still work.
A 301 redirect means the move is permanent; a 302 means it is temporary. Your browser usually follows either one without asking.
When redirects help or hinder
A website might send you to a sign-in page, then back to the page you wanted. Too many redirects in a row slow loading, and a redirect loop can stop a page from opening. Websites should check where a redirect leads so they do not send visitors to a harmful site.