The Configerator repository provides Meta developers with a way to make changes easily and quickly to production services. By default, it pushes changes to all services at Meta in a matter of seconds, and doesn’t have the traditional safeguards that most services have of being able to do extensive testing before releasing a new version of the service. It is one of the main things that enables Meta’s move-fast culture and lets developers iterate quickly and have fast development cycles. However, if not done properly, this can result in many reliability issues. This talk goes over the reliability issues that the Ads organization has had due to these config changes and how we have improved the reliability over time by investing into various safety measures like build time validations, diff-time testing, and helped develop and use a new service that can gradually push config changes.