Working with Custom Post Types in WP-API v2

If you worked with the first version of the WP-API, you know that getting custom post types was really easy.

To get all posts, I could send a GET request to http://scottbolinger.com/wp-json/posts. To get a specific type, I could send my request to http://scottbolinger.com/wp-json/posts?type=event.

There have been some pretty big changes in version 2, which is now in WordPress core.

Custom post types are now hidden from the API by default. I can see why they did this, many themes and plugins added post types that they never intended to be public. Making those public would cause more problems than it would solve.

However, that now means we can’t just add the ‘type’ flag to our request, and expect to get post types back.

How to get custom post types in the WP-API v2

Any custom post type that you want to be available to the WP-API needs to have the show_in_rest = true argument. You can do this in your registration function, or after the post is already registered.

Find available post types

The WP-API lists all available post types at https://YOURSITE.com/wp-json/wp/v2/types

The Register Function

You can add your custom post type to the API when you register it.

Using the ‘book’ post type example from the codex, we just add the show_in_rest argument.

/**
 * Register a book post type, with REST API support
 *
 * Based on example at: https://codex.wordpress.org/Function_Reference/register_post_type
 */
add_action( 'init', 'my_event_cpt' );
function my_event_cpt() {
    $args = array(
      'public'       => true,
      'show_in_rest' => true,
      'label'        => 'Events'
    );
    register_post_type( 'event', $args );
}

The important part is ‘show_in_rest’ => true, that’s what exposes our CPT to the API.

Method 2: Add support after the post is already registered

If you are exposing a CPT that is not in your own plugin, or you need to do it in a different place, you have a couple of options. The first is to use the init action, which is recommend in the official documentation.

add_action( 'init', 'my_custom_post_type_rest_support', 25 );
function my_custom_post_type_rest_support() {
    global $wp_post_types;
    //be sure to set this to the name of your post type!
    $post_type_name = 'book';
    if( isset( $wp_post_types[ $post_type_name ] ) ) {
        $wp_post_types[$post_type_name]->show_in_rest = true;
        // Optionally customize the rest_base or controller class
        $wp_post_types[$post_type_name]->rest_base = $post_type_name;
        $wp_post_types[$post_type_name]->rest_controller_class = 'WP_REST_Posts_Controller';
    }
}

The second option is to use the register_post_type_args filter.

function sb_add_cpts_to_api( $args, $post_type ) {
    if ( 'book' === $post_type ) {
        $args['show_in_rest'] = true;
    }
    return $args;
}
add_filter( 'register_post_type_args', 'sb_add_cpts_to_api', 10, 2 );

This works 99% of the time, but I’ve seen an occasion where this did not work for some strange reason. If you have any trouble use the init hook instead.

Getting Your Posts

Your CPT will be available at your site like this: http://scottbolinger.com/wp-json/wp/v2/book

For more information, please consult the REST API Handbook.

*Updated June 2021

21 comments

  1. So, I’ve tried both mothods but the returned JSON just contain 10 posts (in both methods). Can u tell me why?
    Btw, thank you for the post. Saved my a lot of work.

    1. Hi Matheus, the API returns 10 posts at a time by default. You have to use the page parameter to get more. For example, …wp-json/wp/v2/posts?page=2

  2. Scott, have you tried adding this support and creating a new post with the custom post type? I’ve been trying this and can get it to work fine when posting to /posts. It creates the post without a problem. But then I added support for a ‘course’ custom post type but the post is added without accepting the title, excerpt, or content that I am sending. Nothing is different between the two javascript calls except the /course vs. /posts endpoint.
    Do you think that *should* be working? Or do you think I need to write my own custom route to handle that?

    1. Ugh…please disregard. I found that the CPT didn’t support what I was trying to add through the API. Once I added support, everything started working.

  3. I don’t follow why I have to explicitly allow access to post types if my client is authenticated at the same level as a WordPress administrator.
    A pain!

  4. hi, i am completely new to wordpress in the way of rummaging in the php.files. so with that said where to i find the register_post_type in which file?

  5. Something odd with mine. A bunch of my custom post types working properly, except for 1. Continues to 404 with no rest route, despite having the same code as the rest.
    Any idea what would cause that?

  6. Thank you for this. I really battled to add existing post types. Lots of hours of frustrations sorted out in two min. If only I found your post earlier! :):)

  7. Holy thread resurrection Batman!
    But, is there a way to include all the postmeta data attached to the custom post type?

  8. Thanks for this! Helped me out when I updated my site to v2 and all my cpt calls didn’t work anymore!

Comments are closed.