Used MongoDB as primary database. It holds trip data of NYC taxis for the year 2013. It is a huge dataset and it's primary feature is geo coordinates with pickup and drop off locations. Also used MongoDB's map reduce to process this large dataset for aggregation. This aggregated result was then used to show visualizations.
Used node.js server as backend. Interacts with MongoDB using MongoSkin package which is a wrapper for the MongoDB node.js driver. It uses express for routing and cors package for enabling cors and eyes package for enhancing readability of logs. Also I use nodemon which takes away the effort to restart the server after making changes.