PHP header redirect 301 - what are the implications?

A 301 redirect in PHP using the header function tells the browser that the page has permanently moved to a new location. This is useful for redirecting old URLs to new ones or updating pages that have been relocated. The main implications of using a 301 redirect are:

1. The browser will cache the redirect, so future requests for the old URL will automatically go to the new URL.
2. Search engines will transfer their index entries to the new URL, updating search results accordingly.
3. Users will be automatically directed to the new URL when they request the old one.

It's important to note that a 301 redirect passes link equity (ranking power) to the destination page. If the original page has strong SEO value, the new page will inherit it.

<‌?php
header("Location: https://example.com/new-page", true, 301);
exit;
?>

Critical note: Always call exit (or die) immediately after header(). Without it, the PHP script continues executing, which can cause unexpected output or errors before the redirect takes effect.

Also, use a 301 redirect only when the resource is permanently moved. For temporary moves, use a 302 redirect, which tells browsers and search engines that the relocation is only temporary.