Hooks

Without ACF active, each wpff/… hook below that ACF also has runs as acf/… too. See ACF compatibility.

Hook	Type	Purpose
wpff/init	action	Register groups, options pages and blocks here.
wpff/register_field_types	action	Add your own field type, a subclass of FreeformFields\Fields\AbstractField: $registry->register( new My_Field() ).
wpff/load_value, wpff/format_value, wpff/update_value	filter	( $value, $post_id, $field ). Also /type=…, /name=… and /key=… variants.
wpff/validate_value	filter	( $valid, $value, $field, $post_id ). Return a message string to reject the value. Also /type=, /name= and /key= variants.
wpff/prepare_field	filter	( $field ), before the field is rendered. Return false to hide the field.
wpff/pre_update_value	filter	Return false to skip saving a value.
wpff/save_post	action	( $post_id, $errors ), after a form is saved.
wpff/save_field_group, wpff/delete_field_group	action	After a group is saved or deleted in the admin.
wpff/load_field_groups	filter	All groups, before they are normalized.
wpff/location/matchers	filter	Custom location rules: 'param' => fn( $rule, $screen ) => bool.
wpff/settings/save_json, wpff/settings/load_json	filter	Local JSON folders.
wpff/settings/{name}	filter	A setting value.
wpff/options_autoload	filter	Whether options page values are autoloaded.
wpff/capability	filter	Capability needed to manage field groups. Default: manage_options.
wpff/acf_compat	filter	Whether to define functions with ACF's names.
wpff/fields/google_map/api_key	filter	Google Maps API key. Return '' to use OpenStreetMap.
wpff/fields/google_map/tiles	filter	Tile server: [ 'url' => …, 'attribution' => … ].
wpff/fields/google_map/geocoder_url	filter	A Nominatim-compatible geocoder.
wpff/updates/enabled	filter	Whether to check GitHub releases for plugin updates. Default true.
wpff/updates/manifest_url	filter	URL of the update manifest. Default: update.json of the latest release.

Examples

Reject a value:

add_filter( 'wpff/validate_value/name=isbn', function ( $valid, $value ) {
	if ( $value && ! preg_match( '/^[0-9-]{10,17}$/', $value ) ) {
		return 'Enter a valid ISBN.';
	}
	return $valid;
}, 10, 2 );

Hide a field from non-admins:

add_filter( 'wpff/prepare_field/name=internal_note', function ( $field ) {
	return current_user_can( 'manage_options' ) ? $field : false;
} );