rest-api

<?php 

add_action( 'rest_api_init', 'slug_register_acf' );
function slug_register_acf() {
  $post_types = get_post_types(['public'=>true], 'names');
  foreach ($post_types as $type) {
    register_rest_field( $type,
        'acf',
        array(
            'get_callback'    => 'slug_get_acf',
            'update_callback' => null,
            'schema'          => null,
        )
    );
  }
}
function slug_get_acf( $object, $field_name, $request ) {
    return get_fields($object[ 'id' ]);
}