You can think of this chat app as a chain. If someone is also outside the stadium, then if a user is at the gate of the stadium and is connecting this chat app with the user inside the stadium then they can talk to him.
To use this chat app, the distance from one smartphone to another smartphone should be 200 feet.
According to Fire Chat, this app works without the internet. It works even if there is no cellular network. It can be used in planes, public transport, cruise ship, campus, and crowded events. The only need for this is that some people are using it around there.
You can send messages and photos from this chat app. The company claims that private messages are peer-to-peer encrypted.
Fire Chat users can create chat rooms that can be public or private. If the internet is turned on then in this case this app works through the internet in a normal way.
To use it, users have to install Fire Chat on their mobile phones and create a free account.
One thing to keep in mind is that this app is not as secure as WhatsApp and Telegram. Since it works via WiFi and Bluetooth, it is not secure. The developer of this chat app had said in an interview to Wired that people have to understand that it is not a tool made for any wrong purpose and it is not for secure and private communication.