title: What is verify token in Facebook Realtime API
body: <p>I'm trying to implement Facebook Realtime api with my application. I want to pull the feeds from my 'facebook PAGE'.
  I've obtained app_access_token...</p>
  
  <pre><code>app_access_token = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx'       
  
  url = 'https://graph.facebook.com/' + FB_CLIENT_ID + '/subscriptions?access_token=' + app_access_token
  
  url_params = {'access_token':app_access_token,'object':'page', 'fields':'feed', 'callback_url':'http://127.0.0.1:8000/fb_notifications/', 'verify_token' : 'I am taking a random string here...'}
  
  urlResponse = call_url(url, url_params)
  </code></pre>
  
  <p>Everytime I call the url with url parameters, I get error : HTTP Error 400: Bad Request
  But If I call the url without url parameters, I get <code>{"data": []}</code></p>
  
  <p>Please note that in url parameters, I'm taking verify_token, a random string and callback_url is not same as the redirect_url parameter for the facebook application.(just wanna know is it necessary to put the same url here?) </p>
  
  <p>Please tell me what I'm doing wrong?
  I'm using python/django to implement.</p>