Chat application network architectures are primarily divided into: centralized model, federated model, relay model, and P2P model. Chat software developed by major companies primarily uses a centralized server network architecture, such as WhatsApp and Telegram. Signal App also follows this model. Only large companies can run their own servers and have the greatest control. The XMPP protocol and Matrix protocol use a federated server network architecture. The most famous example of a federated server network architecture is Email. Users can choose which federated server to use. Servers communicate with each other, and users do not need to know which server their friends are using. Keychat and Simplex chat use a relay architecture. Users can choose which relay server to use. The main difference from the federated model is that relay servers do not communicate with each other. In the relay model, users find out which relay their friends use, adding user tasks but simplifying server operations. Each relay operates independently, simplifying network design and reducing maintenance. Since relays do not communicate with each other, this setup reduces data exposure risks and improves privacy. Keet.io uses a P2P model. Keet may be more suitable for large-scale group chats, whereas it might be less appropriate for one-on-one chats or smaller groups. Keet requires chat participants to be online simultaneously, or at least one party needs to be continuously online. (If there are any mistakes, please reply. Thanks)