title: When to Redis? When to MongoDB?
body: <p>What I want is not a comparison between Redis and MongoDB. I know they are different; the performance and the API is totally different.</p>
  
  <p>Redis is very fast, but the API is very 'atomic'. MongoDB will eat more resources, but the API is very very easy to use, and I am very happy with it.</p>
  
  <p>They're both awesome, and I want to use Redis in deployment as much as I can, but it is hard to code. I want to use MongoDB in development as much as I can, but it needs an expensive machine.</p>
  
  <p>So what do you think about the use of both of them? When to pick Redis? When to pick MongoDB?</p>