What do Mexico, Australia and South Africa have in common in the Uber world? Complicated phone anonymization systems! In 2015, Uber scaled its anonymization system 10x to ensure user privacy worldwide. While purchasing phone numbers from Twilio is easy, scaling a system to support millions of users in over 30 countries while being cost efficient is not. We learned the intricacies of each country and came up with creative solutions for a seamless communication experience for our users.