// IndexController.php
class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
		$data = array(...);
		
		$this->view->data = Zend_Json::encode($data);	
	}	
}

The result in general is a specially formatted string. So you can simply set it up to a view member variable and pass it to the view.

// index/index.phtml
echo $this->data

In that case you’ve a .phtml file to maintain, so lets just return the string and “setNoRender” the view in our second try.

// IndexController.php
class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
		$data = array(...);
		
		echo Zend_Json::encode($data);	
		
		$this->_helper->viewRenderer->setNoRender(true);
	}	
}

Actually this is pretty much the most clear solution, but actually you can output the JSON string and simply exit() as it’s shown in our third example.

// IndexController.php
class IndexController extends Zend_Controller_Action
{
	public function indexAction()
	{
		$data = array(...);
		
		echo Zend_Json::encode($data);	
		
		exit();
	}	
}

Which one is to be used is up to the developer’s choice, mine is the third one as it’s the minimal one.