If you’ve updated your WordPress permalinks from
/postname/ → /category/postname/,
you may notice old links returning 404 errors. That’s because WordPress can’t automatically redirect visitors to the new category-based URLs.
Infrastructure Context
In live WordPress environments, issues like this are rarely isolated. We typically see them as part of a broader infrastructure pattern involving updates, plugin compatibility, performance constraints, or database integrity. Teams running WordPress at scale treat these issues as ongoing operational concerns—not one-off fixes—because reliability, security, and continuity matter once a site is in production.
Here’s a quick fix that keeps your SEO intact and sends users to the right place.
⚙️ Step-by-Step
Log in to your WordPress admin.
Go to Appearance → Theme File Editor (or access your site files via FTP).
Open your theme’s functions.php file.
Paste the code below at the bottom:
add_action('template_redirect', function() {
if (is_404()) {
global $wpdb;
$request_uri = trim($_SERVER['REQUEST_URI'], '/');
$slug = basename($request_uri);
$post_id = $wpdb->get_var($wpdb->prepare(
"SELECT ID FROM $wpdb->posts WHERE post_name = %s AND post_status = 'publish' LIMIT 1",
$slug
));
if ($post_id) {
wp_redirect(get_permalink($post_id), 301);
exit;
}
}
});
Now, any visitor who lands on an old /postname/ URL will be automatically redirected to the correct /category/postname/ version — no broken links, no SEO loss.
Simple, quick, and future-proof.
Need this fixed fast in production?
We resolve broken WordPress sites, failed updates, plugin conflicts, and critical errors as part of our managed WordPress operations.
About the Author
Martin is the Lead WordPress Infrastructure & Security Engineer at CriticalWP, where he leads enterprise WordPress architecture, security hardening, performance optimization, and incident response for high-traffic and mission-critical platforms. He specializes in diagnosing complex WordPress failures, preventing security incidents, and building resilient infrastructure for organizations that rely on WordPress at scale.