Add custom field to WordPress REST API

Sometimes we may need to add custom fields to existing core WordPress REST API, which we may also need in the module for Custom Gutenberg Block development.
In this blog we will learn about how to do just that.

Add custom field to ‘user’ endpoint.

We will use register_rest_field function and hook it to rest_api_init hook. So add this to your functions.php

add_action( 'rest_api_init', 'adding_user_meta_rest' );

     * Adds user_meta to rest api 'user' endpoint.
    function adding_user_meta_rest() {
        register_rest_field( 'user',
                'get_callback'      => 'user_meta_callback',
                'update_callback'   => null,
                'schema'            => null,

     * Return user meta object.
     * @param array $user User.
     * @param string $field_name Registered custom field name ( In this case 'user_meta' )
     * @param object $request Request object.
     * @return mixed
    function user_meta_callback( $user, $field_name, $request) {
        return get_user_meta( $user['id'] );

Access registered field using REST API

Let’s hit the following endpoint in the browser /wp-json/wp/v2/users/

There is our custom meta field ‘user_meta’

Access registered field using WordPress Data module.

You can now access the user field in WordPress data module for block development as well.
Let’s run this in console on the WordPress editor page.'core').getCurrentUser();
There is our custom meta field ‘user_meta’

That’s all folks

Leave a Reply