Maria got the idea when her friends were concerned about her safety while travelling to places, especially those that are far away. As a result, she came up with an idea to ensure her safety while keeping her friends in the loop in case anything happens. Our target users are people who travel often. Transponder is especially useful for people when they travel using any form of transportation. Transponder serves is the first point of contact to others of a user's emergency. For example, if a person were to be walking home through an unsafe neighborhood, Transponder will inform his or her emergency contacts in the event that something bad happened to him or her, e.g. a mugging or kidnapping, and his or her location. This can apply to any emergency scenario, such as car accidents, natural disasters, and criminal activity. Key features that we are most proud of are how the app works and what allows it to work. The app works by prompting the user to set an interval of time which sets how frequent notifications are to be sent. The user must reply to the notification before the next one is sent in order to let the app know the user is safe, but if the user does not do this, then a message with the user's GPS coordinates is sent to all the emergency contacts from a python backend application. Through this system, it will continue to work even if the phone is compromised, e.g. out of batteries or stolen, and can alert others without the need for the user to alert others at the moment of crisis.