When a massive campaign like Justin Bieber's Hotline Bling promotion is built, it relies on a few key tools: An Amazon S3 Bucket for storing media, a Rackspace Database for handling large volumes of data, and Twilio for making phone calls. The mastermind behind the operation, Oliver Muoto, used these tools to build a hotline that could scale to meet the demands of Biebermania, with the ability to handle hundreds of thousands of calls in just one minute. With the Twilio API being well-built out, Oliver was able to easily adjust the system to handle different volumes of traffic and stream high-quality audio files over the phone to fans worldwide. The campaign's success is a testament to the power of using the right tools to build scalable technology that can keep up with unexpected demands, such as those posed by a celebrity like Justin Bieber.