stateful-textcaptcha-request.php

<?php
session_start();

$url = 'http://api.textcaptcha.com/example.json';
$captcha = json_decode(file_get_contents($url),true); 
if (!$captcha) {
 $captcha = array( // fallback challenge
  'question'=>'Is ice hot or cold?',
  'answers'=>array(md5('cold'))
 );
 // + capture error info & log
}

// display question to user as part of form
echo htmlentities($captcha['question']);

// store answers in session
$_SESSION['captcha_ans'] = $captcha['answers'];