Build a Real-Time Chat App in Android with PubNub (Kotlin + MVVM) – Part 1: Introduction


By Revansiddappa Kalshetty

Real-time messaging has become a critical feature in today’s mobile apps — from social networks to support systems and team collaboration tools. But building it from scratch can be challenging: server setup, websockets, message queuing, typing indicators, presence, and so much more.

Luckily, you don’t have to do it all yourself.

In this tutorial series, I’ll show you how to build a modern, scalable in-app chat feature for Android using Kotlin, MVVM architecture, and PubNub, a powerful platform that handles the heavy lifting of real-time infrastructure.

What You’ll Build

Here’s a sneak peek of the features we’ll implement in this tutorial series:

  • Real-time messaging using PubNub

  • Chat history with message persistence

  • Online/offline presence tracking

  • Typing indicators

  • Media sharing (optional)

  • Push notifications (optional)

  • Secure access with PubNub Access Manager (PAM)

  • Multi-channel & group chat support

All of this will be built using MVVM, LiveData, and clean, testable Kotlin code.

Tools & Tech Stack

Technology Purpose
Kotlin Modern Android language
MVVM Scalable app architecture
PubNub Real-time messaging infrastructure
LiveData Reactive UI updates
RecyclerView Chat list UI
Firebase (opt) Push notifications

We’ll keep things modular and extendable so you can plug this chat system into any kind of app: social, gaming, e-commerce, or internal tools.

Why PubNub?

PubNub provides a real-time data network that powers messaging, presence, and sync — with just a few lines of code. Here's what makes it a great fit for in-app chat:

  • Fast and scalable real-time communication

  • No backend to maintain

  • Built-in message history and presence APIs

  • Easy media/file sharing support

  • Developer-friendly SDKs and docs

Plus, it supports both 1:1 and group conversations, making it flexible for all chat scenarios.

Full Tutorial Series

This is Part 1 of a full tutorial series. Here's what’s coming up (links will be added as published):

✅ = Live  🔄 = Coming Soon

  1. ✅ Introduction (this post)

  2. 🔄 Project Setup (Kotlin + MVVM + PubNub SDK)

  3. 🔄 Initializing PubNub in MVVM

  4. 🔄 Designing the Chat UI

  5. 🔄 Sending Messages

  6. 🔄 Receiving Messages

  7. 🔄 Loading Chat History

  8. 🔄 Presence & Typing Indicators

  9. 🔄 Reconnection & Error Handling

  10. 🔄 Media Sharing

  11. 🔄 Push Notifications

  12. 🔄 Multi-Channel & Group Chats

  13. 🔄 Security with PAM

  14. 🔄 Reactions, Metadata & Message Enrichment

  15. 🔄 Final Testing & Deployment

What’s Next?

In Part 2, we’ll:

  • Set up a new Android project using Kotlin

  • Organize it using the MVVM architecture

  • Add PubNub SDK and connect to the messaging network

Follow me on Medium or bookmark this series to stay updated as each part is released.

💬 Questions or Ideas?

Got a use case in mind? Want to see a certain feature added?
Drop a comment below, or connect with me on X (formerly Twitter) @revansiddappa1. Let’s build this together — one feature at a time.

Are you ready to bring your Android app to life with chat? Let’s get started! 


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