title: What are the differences among server-key, android-key, browser-key and iOS key in Google API?
body: <p>I am using GCM in my android app. To use GCM service we need to create Google API key. So, I have created API keys for android, server and browser key.
  It seems that my app working for all of those keys whatever key i use in my app.</p>
  
  <p>I changed the key to android, browser and server key from my app. All keys are working from my android app. </p>
  
  <p><strong>My question is why both browser and server key also working from my android app? And why we need to create specific key like browser key, server key as all keys are working from android app instead of android key only?</strong></p>