Function and usage of get_blog_option() in wordpress


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    The get_blog_option() function in WordPress is a powerful tool for developers working in a multisite environment. It allows you to retrieve the value of a specific option from a given blog within the network. Here's a detailed breakdown of its usage:

    Function Signature

    get_blog_option( int $id, string $option, mixed $default_value = false ): mixed

    Function Overview

    • Purpose: Retrieves the value of a specified option for a given blog ID.
    • Use Case: Particularly useful in multisite setups where you need to access options from different sites within the network.


    • The function returns the value of the $option from the blog with the ID $id.
    • If the option doesn't exist or has no value, the function returns false or the specified $default_value.
    • This function is often used during plugin installation or updates to check the existence of certain options or to determine if an upgrade is necessary.
    • Serialized data associated with the option will be unserialized upon retrieval.


    1. $id (int, required): The ID of the blog from which you want to retrieve the option. You can pass null to refer to the current blog in context.
    2. $option (string, required): The name of the option you want to retrieve. It should not be SQL-escaped.
    3. $default_value (mixed, optional): The default value to return if the option does not exist. Defaults to false.

    Return Value

    • Type: mixed
    • Description: The function returns the value set for the option. If the option doesn't exist, it returns the $default_value or false.

    Sample Usage

    // Example 1: Retrieve a specific option from a specific blog
    $blog_id = 2; // Assume this is the ID of the blog
    $option_name = 'my_custom_option';
    $default = 'default_value';
    $value = get_blog_option( $blog_id, $option_name, $default );
    // Example 2: Retrieve an option from the current blog
    $current_blog_option = get_blog_option( null, 'some_option', 'default' );


    • This function is part of WordPress's multisite features. It is not applicable for single-site installations.
    • Always check if the function exists before using it, especially if your plugin or theme could be used on single-site installations.


    get_blog_option() is essential for retrieving options from different blogs in a WordPress multisite network. Its ability to handle serialized data and provide default values when options are not set makes it a robust solution for plugin and theme developers.

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