# wp_siteurl in config
In WordPress, `WP_SITEURL` is a constant that can be defined in the `wp-config.php` file to specify the WordPress address (URL). This constant determines the location of your WordPress core files and is used by the `site_url()` API function.
Purpose of `WP_SITEURL` in `wp-config.php`:
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**Overrides database value:**
When defined in `wp-config.php`, `WP_SITEURL` takes precedence over the `siteurl` value stored in the WordPress database's `wp_options` table.
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**Reduces database calls:**
Setting this constant can potentially reduce the number of database queries required to retrieve the site URL during page loads.
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**Temporary URL changes:**
It is particularly useful for temporarily changing the WordPress address, such as during site migration or troubleshooting when you cannot access the WordPress admin dashboard.
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**Previewing on temporary domains:**
Allows previewing a site on a temporary domain without altering the database, preventing redirection to the old server.
How to define `WP_SITEURL`:
- Access `wp-config.php`: Connect to your server using FTP or your hosting provider's file manager and locate the `wp-config.php` file in your WordPress installation directory. - **Edit the file:** Open `wp-config.php` in a plain text editor. - **Add the definition:** Add the following line before the line that says `/* That's all, stop editing!` `Happy publishing.` `*/`:
Code
``` define('WP_SITEURL', 'http://yourdomain.com'); ```