At Booking we have more than a million properties selling their rooms to our customers. We have approximately 1000 events per minute from them leading to total 500 GB of data for partner events alone. In order to make sure we receive the relevant inventory from our partners we A/B test various new features. There were more than 100 experiments focusing on availability alone in one quarter. In my talk I ll be talking about A/B testing at Booking, different technologies like Hadoop, Hbase, Cassandra, Kafka etc that we use to store and process large volumes of data and building up of metrics to measure the success of our experiments.