The way I look at Redis is a service that helps to off-load main db. Obvious example is how people use it as a cache. But it has other use, such as: - Leaderbo

The way I look at Redis is a service that helps to off-load main db. Obvious example is how people use it as a cache. But it has other use, such as: - Leaderboard: Redis shines when we need to store ranking data. - Geo Query: Instead of query geo spatial index directly from MongoDB. I use Redis and feed the id back into MongoDB - Track Occurence Of Event: Let's say we need to keep track state of an user - Set of data In other words, I treat Redis as a network/distributed data structure, which I can implement in the main db, but will require heavy read/write.