src/admin/class-papi-admin-ajax.php
public function get_shortcode() {
		$shortcode = papi_get_qs( 'shortcode' ) ?: '';
		$shortcode = html_entity_decode( $shortcode );
		$shortcode = wp_unslash( $shortcode );

		wp_send_json( [
			'html' => do_shortcode( $shortcode )
		] );
	}
public function get_shortcode() {
		$shortcode = papi_get_qs( 'shortcode' ) ?: '';
		$shortcode = html_entity_decode( $shortcode );
		$shortcode = wp_unslash( $shortcode );

		wp_send_json( [
			'html' => do_shortcode( $shortcode )
		] );
	}
Get shortcode via GET.

GET /papi-ajax/?action=get_shortcode