The Snapchat Best Friends List is a feature that highlights the people you interact with the most on the app. It is determined by factors such as the frequency of snaps and chats exchanged between users. Best Friends appear at the top of your chat list and are marked with special emojis, like the (red heart) or (yellow heart), which indicate different levels of friendship. Snapchat keeps this list private, meaning only you can see who your Best Friends are.