Safety Check: Streamlining deployment around the world

What this post added

This post details the engineering evolution of the Safety Check feature, highlighting the transition from manual processes to automated deployment and monitoring. It showcases the development of a robust activation algorithm leveraging the social graph, the implementation of rate-limiting services for stability, and the creation of proactive testing systems ('shadow launches'). Furthermore, it describes the automation of the launch process through an internal tool and the use of a Messenger bot for post-launch monitoring, demonstrating a significant advancement in the speed, reliability, and scalability of deploying critical features.