Understanding the Difference Between site_url(), home_url(), and get_bloginfo(‘url’) in WordPress

If you are a WordPress developer and would like to join in a company, one of the critical viva questions might be the difference between these three functions in WordPress. It might be a little bit tough because you never think about it and usually we don’t have to think about things like this topic.

Let's dive deep to explore what are they and how to use them.

site_url():
— Returns the URL to the site’s WordPress installation.
— Versatile and useful for generating URLs to various parts of the WordPress installation.
— Ideal for creating dynamic links, and referencing core files, plugins, and themes.
— Helpful in multisite setups to retrieve site-specific base URLs within the network.
2. home_url():
— Returns the URL to the home page of the site.
— Used to generate the URL to the main site’s homepage.
— Often interchangeable with site_url() for the main site URL.

3. get_bloginfo(‘url’):
— Retrieves the URL to the home directory of the WordPress installation.
— Used to fetch various site information parameters set in WordPress settings.
— Commonly used to retrieve the site URL set in Settings ->General-> WordPress Address (URL).

Distinguishing these functions:

home_url() and site_url() may appear similar, especially when WordPress is installed in the root directory. However, their differences become evident when WordPress is set up in a subdirectory or if they're used within specific contexts. home_url() typically points to the front-end home page URL, while site_url() refers more generally to the WordPress installation's base URL.

On the other hand, get_permalink() has a focused use case—it fetches the specific URL of a post or page. This function aids in dynamically generating or retrieving individual post URLs, critical when building themes, plugins, or manipulating content within WordPress.

Here is a real-life use case:

// Function to get the URL for a custom API endpoint using home_url()
function get_custom_api_endpoint_url() {
    $api_slug = 'custom-api'; // Replace 'custom-api' with your desired endpoint slug
    $api_url = home_url('/' . $api_slug . '/'); // Generates the URL for the custom API endpoint
    return $api_url;
}

// Function to get the URL for a specific page using site_url()
function get_specific_page_url($page_slug) {
    $page_url = site_url('/' . $page_slug . '/'); // Generates the URL for a specific page
    return $page_url;
}

// Usage example:
$custom_api_url = get_custom_api_endpoint_url();
echo 'Custom API Endpoint URL: ' . $custom_api_url . '<br>';

$about_page_url = get_specific_page_url('about-us');
echo 'About Us Page URL: ' . $about_page_url;

get_custom_api_endpoint_url() uses home_url() to generate a URL for a custom API endpoint. You can replace 'custom-api' with your desired endpoint slug.

get_specific_page_url($page_slug) utilizes site_url() to dynamically generate the URL for a specific page based on the provided page slug.

Each function serves a unique purpose and can be utilized based on the context and requirements of your WordPress project. By leveraging these functions effectively, you can handle URLs, links, and resources within your WordPress site more efficiently.