WordPress itself handles how an HttpException is displayed to the user. In a nutshell, those exceptions are converted into a WP_Error which is then handled by WordPress via wp_die function.

This means, that the following types of requests are supported:

• ✅ Ajax
• ✅ JSON
• ✅ JSONP
• ✅ XMLRPC
• ✅ XML
• ✅ All other types e.g. HTML

throw new HttpException(headers: ['My-Header' => 'Value 123']);

$exceptionHandler = ExceptionHandler::getOrCreate();
$exceptionHandler->onException(CustomException::class, fn($ex) => echo "A custom exception has been raised");

Ensure to add handlers which supports all types of possible requests e.g. JSON, XML, etc

If you are using Sage theme, you would need to register or re-register this exception handler after the application is configured. Otherwise, this exception handler might be overrided.

// themes/sage/functions.php

Application::configure()
    ->withProviders([
        App\Providers\ThemeServiceProvider::class,
    ])
    ->boot();

ExceptionHandler::register(force: true); // We are using force true in case the ExceptionHandler has been registered before e.g. in a plugin