Dynamic Options

The options parameter of the select, radio, combobox and toggle_group controls accepts either a fixed list or a {{token}} that pulls the choices from WordPress data at render time.

Tokens are resolved in the browser through the WordPress core data package (@wordpress/core-data), which means no extra PHP is needed to populate a field with posts, users or terms.

1) Static Options

Write the choices as Label : value, separated by commas:

'options' => 'Option 1 : option_1, Option 2 : option_2',

If the : part is omitted, the text is used as both the label and the value. An array of ['label' => ..., 'value' => ...] items is accepted as well.

2) Dynamic Options

A {{token}} anywhere in the value switches the field to dynamic mode:

'options' => '{{posts}}',

Static text is ignored as soon as the value contains a token, so the two cannot be mixed. Several tokens can be combined and their results are merged into a single list, with duplicates removed:

'options' => '{{pages}} {{posts?type=book}}',

3) Available Tokens

Token	Source	Label	Stored value
`{{posts}}`	Posts	Post title	Post ID
`{{pages}}`	Pages	Page title	Page ID
`{{users}}`	Users	Display name	User ID
`{{categories}}`	Categories	Term name	Term ID
`{{tags}}`	Tags	Term name	Term ID
`{{menus}}`	Navigation menus	Menu title	Menu ID
`{{taxonomies}}`	Registered taxonomies	Taxonomy name	Taxonomy slug
`{{post_types}}`	Registered post types	Singular name	Post type slug

{{taxonomies}} returns the list of taxonomies, not the terms inside them. Only category and tag terms can be listed, through {{categories}} and {{tags}}.

4) Custom Post Types

Use the type parameter together with {{posts}} and pass the post type slug:

'options' => '{{posts?type=book}}',
'options' => '{{posts?type=product&per_page=50&orderby=title&order=asc}}',

type is not forwarded to the REST API; it selects which post type is queried. Without it, {{posts}} queries post and {{pages}} queries page.

The post type must be registered with show_in_rest => true, otherwise it has no REST endpoint and the field stays empty.

5) Parameters

Everything after ? is passed to the REST API endpoint backing that token, so any argument the endpoint supports can be used:

'options' => '{{posts?type=book&per_page=100&status=publish}}',
'options' => '{{users?roles=administrator&per_page=10}}',
'options' => '{{categories?per_page=100&orderby=name&hide_empty=true}}',
'options' => '{{taxonomies?type=post}}',

Two arguments are easy to get wrong:

roles (plural) is the users endpoint argument and expects role slugs, not role.
author expects a user ID, not a login name: {{posts?author=5}}.

6) How Many Items Are Returned

The WordPress REST API returns 10 items per request by default and never accepts a per_page above 100. Values such as per_page=500 or per_page=-1 are capped at 100 instead of failing the request. per_page=all is accepted as a spelling of the same thing.

That limit makes select, radio and toggle_group unsuitable for large collections: they render a single page of results and offer no way to reach the rest.

7) Searching Large Collections

The combobox control searches server side when its options come from a token. What is typed in the field is sent to the REST API as the search argument, so a collection of any size stays fully reachable regardless of per_page:

[
    'fieldType'  => 'combobox',
    'name'       => 'member',
    'fieldLabel' => 'Member',
    'options'    => '{{posts?type=member}}',
]

For this control, per_page only determines how many entries are listed before anything is typed; it does not have to cover the whole collection.

The record matching the stored value is fetched separately, so a saved selection keeps its label even when it falls outside the current search results.

Searching server side applies to {{posts}}, {{pages}}, {{users}}, {{categories}}, {{tags}} and {{menus}}. {{taxonomies}} and {{post_types}} return short, complete lists and are filtered in the browser.

8) Token Field Suggestions

The suggestions parameter of the token_field control is a plain comma-separated list of strings and does not support {{tokens}}:

'suggestions' => 'Africa, Europe, Asia',