How to redirect index.php to another domain

# 301 an entire domain to a new one, keeping paths and query strings
RewriteEngine On
RewriteCond %{HTTP_HOST} ^(www\.)?olddomain\.com$ [NC]
RewriteRule ^(.*)$ https://newdomain.com/$1 [R=301,L]

Method 1: .htaccess (recommended)

The block above catches every request to the old domain — with or without www — and forwards it to the same path on the new domain. %{HTTP_HOST} matching prevents redirect loops if both domains point at the same server, $1 carries the path across, and query strings (?utm_source=...) pass through automatically with RewriteRule.

If you only need one page redirected rather than the whole site, mod_alias is simpler:

# Single page to a specific new URL
Redirect 301 /old-page/ https://newdomain.com/new-page/

Method 2: PHP redirect in index.php

Sometimes you can't touch .htaccess — a bare account with only an index.php, or a host that ignores override files. This goes at the very top of the file, before any output, including whitespace:

<?php
// 301 everything to the new domain, preserving the requested path
$target = 'https://newdomain.com' . ($_SERVER['REQUEST_URI'] ?? '/');
header('HTTP/1.1 301 Moved Permanently');
header('Location: ' . $target);
exit;

Which one, when

• Moving a whole site to a new domain: .htaccess RewriteRule. Set it, then use Google Search Console's Change of Address tool on the old property.
• Old domain is just a parked shell with one file: the PHP version is fine — it's the only thing that file will ever do.
• Only some URLs move: individual Redirect 301 lines, or the RewriteRule pattern narrowed to those paths.
• Temporary move (rare — seasonal campaigns, maintenance): use 302/307 instead of 301 so search engines keep the original URL indexed.

Test it before you trust it

Don't test 301s in your normal browser — browsers cache them aggressively, so a mistake can haunt you after you've fixed it. Use curl and check both the status and the Location header:

curl -sI https://olddomain.com/some/deep/page/?ref=test | grep -iE '^(HTTP|location)'

# You want exactly:
# HTTP/2 301
# location: https://newdomain.com/some/deep/page/?ref=test

Three things to verify: the status is 301 (not 302), the path and query string survived, and it happens in one hop. If you see http → https → www → new domain chains, collapse them — every extra hop wastes crawl budget and slows real visitors.

The mistakes that cost rankings

1. Redirecting everything to the new homepage. Path-blind redirects turn every earned backlink into a soft-404 experience. Always preserve paths unless a page genuinely has no equivalent.
2. Removing the redirect too soon. Google's redirect documentation treats permanent redirects as the signal that consolidates the old URL into the new one — keep it a minimum of 12 months, and if the old domain renewal is cheap, keep it forever.
3. Forgetting Search Console. The Change of Address tool actively tells Google about the move instead of waiting for it to be inferred.
4. Redirect loops. If both domains resolve to the same document root, a rule without the HTTP_HOST condition redirects the new domain to itself. The condition in Method 1 is not optional.
5. Testing in a cached browser. See above — curl or a private window, always.

FAQ

Thomas McKee

Owner, Thomas McKee Website Design & SEO Solutions — building, hosting, and ranking websites from Springfield, Missouri since 1996. 600+ projects, six straight years Best SEO Springfield MO. What we do