How to Share Users and Logins Between WordPress Sites

Updated October 2026: re-tested on WordPress 7.1 with two installs sharing one database. First published in 2018.

This guide sets up two separate WordPress installs, Site A and Site B, so they share the same user accounts and the same login: log in on one and you are logged in on the other. I first needed it in 2018, when I added a bbPress and BuddyPress community (Site B) next to a main site (Site A) that had to stay a separate install. Both were on the same server, which is what makes this approach possible.

Before you start: is this the right approach?

• If you can start fresh, use Multisite. A WordPress Multisite network shares users and logins between its sites out of the box, with no wp-config changes.
• If the sites are on different servers or different domains, this method will not work. It needs one database and cookies on one domain. The WP Remote Users Sync plugin syncs users over HTTP instead. As of October 2026 it was last updated in October 2025 and tested up to WordPress 6.8, so test it on a staging copy first.

Requirements

• Both sites use the same database, with different table prefixes.
• Both sites are on the same domain, in subdomains or subfolders.
• You can edit wp-config.php on both sites, over FTP or your hosting file manager.
• A fresh backup of the database and both wp-config.php files. I use WPvivid on this site, but any backup plugin that covers the database works.

Step 1: Put Site B in Site A’s database

Check Site A’s table prefix

Open Site A‘s wp-config.php and find this line:

$table_prefix = 'wp_';Code language: PHP (php)

It is usually wp_. If yours is different, use your prefix wherever this guide says wp_.

Install Site B with a different prefix

Install WordPress for Site B in a subdomain or subfolder, pointing it at Site A’s database but with its own table prefix. I use com_, short for community. If your installer does not let you choose the database or prefix, change them afterwards in Site B’s wp-config.php:

define( 'DB_NAME', 'siteAdatabase' );
define( 'DB_USER', 'siteAuser' );
define( 'DB_PASSWORD', 'siteApassword' );

$table_prefix = 'com_';Code language: PHP (php)

Step 2: Point Site B at Site A’s users

Open Site B‘s wp-config.php and add these lines just above the That’s all, stop editing! comment:

define( 'CUSTOM_USER_TABLE', 'wp_users' );
define( 'CUSTOM_USER_META_TABLE', 'wp_usermeta' );
/* That's all, stop editing! Happy publishing. */Code language: JavaScript (javascript)

From now on Site B ignores its own com_users table. Site B’s original admin account stops working, and you log in to Site B with your Site A username and password.

Step 3: Give yourself a role on Site B

Logging in now works, but /wp-admin/ on Site B answers Sorry, you are not allowed to access this page. Roles are stored per site, in a user meta row named after the site’s table prefix: wp_capabilities for Site A and com_capabilities for Site B. Your account only has the first one.

Add the second one in phpMyAdmin or Adminer. Open the wp_usermeta table and find the wp_capabilities row of your admin user:

Create a new row with the same user_id (usually 1), com_capabilities as the meta_key (your Site B prefix plus capabilities), and the same meta_value. Leave umeta_id empty so it auto-increments.

Or run the equivalent SQL:

INSERT INTO wp_usermeta (user_id, meta_key, meta_value)
VALUES (1, 'com_capabilities', 'a:1:{s:13:"administrator";b:1;}');Code language: JavaScript (javascript)

Give every shared user a role automatically

The same applies to everyone else. A user who registers on Site A can log in to Site B but has no role there, and Site B’s Users screen shows them as No role for this site. To give them Site B’s default role (Settings > General > New User Default Role) the first time they visit Site B, add this snippet to Site B:

// Site B: give shared users who have no role on this site the default role.
add_action( 'init', function () {
	$user = wp_get_current_user();
	if ( $user->exists() && empty( $user->roles ) ) {
		$user->set_role( get_option( 'default_role' ) );
	}
} );Code language: PHP (php)

It also gives the default role back to anyone you later set to “No role for this site” on Site B, so use it only if every Site A user should have access to Site B.

Step 4: Share the login cookie

The sites now share accounts, but you still have to log in on each one separately, because each install names and signs its login cookie differently. Three things have to match on both sites. When I tested, the shared login failed as long as either the cookie name or the keys were still different:

• the cookie name, set by COOKIEHASH (by default a hash of each site’s own URL, so it differs),
• the security keys and salts, which sign the cookie,
• the cookie domain, set by COOKIE_DOMAIN, so a cookie set on one subdomain is sent to the other.

Add these lines to both wp-config.php files, using Site A’s address in both:

define( 'COOKIE_DOMAIN', 'yourwebsite.com' );
define( 'COOKIEHASH', md5( 'https://yourwebsite.com' ) );
/* That's all, stop editing! Happy publishing. */Code language: JavaScript (javascript)

Then copy the eight keys and salts from Site A‘s wp-config.php over the ones in Site B‘s:

define( 'AUTH_KEY', 'copy the value from Site A' );
define( 'SECURE_AUTH_KEY', 'copy the value from Site A' );
define( 'LOGGED_IN_KEY', 'copy the value from Site A' );
define( 'NONCE_KEY', 'copy the value from Site A' );
define( 'AUTH_SALT', 'copy the value from Site A' );
define( 'SECURE_AUTH_SALT', 'copy the value from Site A' );
define( 'LOGGED_IN_SALT', 'copy the value from Site A' );
define( 'NONCE_SALT', 'copy the value from Site A' );Code language: JavaScript (javascript)

Changing Site B’s keys logs everyone out of Site B once. After that, logging in on either site logs you in on both, and logging out of one logs you out of the other too, because both sites read the same session list from wp_usermeta.

For the role snippet in step 3, add it with a code snippets plugin on Site B rather than in the theme. This guide shows how.