In a real-time Chat App, we use chat API's from quickblox, XMPP, WebSockets, Twilio, etc to achieve messaging features where it can be one-to-one or group chat. Also, we can work with firebase for messaging and notifications if needed. Along with additional features like Media file transmission, Notifications, Temporary content like status and stories, Message broadcasting, and many more.
Our previous projects have the real-time messaging services, audio/video chat [One to one/Group], Notifications, etc. feature implemented along with file sharing, location sharing, document sharing as well as filters and stickers.
The required technology stack for this would include Kotlin with android studio and SDKs for android app and Swift with Xcode and SDKs for IOS app, for backend and APIs, we can use Firebase.
Let's connect in a private chat to discuss your requirement and our queries. I also have some other suggestions that could be added to this app to make it more interactive.