Why? By default in WordPress you can only use the valid fields which are specified by each post type. Read more on WordPresss REST API documentation. This post is useful to you if you might be receiving an error as following. code “rest_invalid_param” message “Invalid parameter(s): orderby” How can you check which fields are available … Continue reading WordPress REST API. Sorting/Orderby for custom meta fields in WordPress and fixing “Invalid parameter(s): orderby”