Cross Chat

Communication Barrier? Not Anymore!

With Cross Chat, you can communicate with people across languages, countries, and locales. For eg:

• You are chatting with a person from Spain
• They send messages in Spanish
• You get the original message in real-time
• And the translated text according to your preferred language (eg. English)

Note: The translations may take 2-10 seconds depending on message length

Check out the demo video here to see Cross Chat in action.

Its primary focus is on:

• Breaking language barriers in real-time text conversations
• Server-driven translations with client-side flexibility
• Clean separation between messaging and translation concerns

This project was built as part of a Hackathon hosted by lingo.dev from 31/01/2026 to 8/02/2026.

You can download the first pre-release version of the Cross Chat Android app here: v1.0.0-alpha.1

Note: The first alpha release contains some bugs, as building a production-ready application within a week wasn’t feasible for me. However these issues will be addressed in upcoming releases 🙂

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Cross Chat demonstrates how multilingual chat can be implemented in a scalable, production-friendly way using modern Android and backend technologies.

Core Features

• Real-time Messaging – Instant delivery using Socket.IO
• Auto Translation – Messages translated based on the user’s preferred language
• Modern UI – Jetpack Compose with Material 3
• Offline First – Local caching with Room Database
• Secure Authentication – JWT-based authentication

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🧰 Tech Stack

Android App (Frontend)

• UI: Jetpack Compose, Material 3 UI
• App Navigation: Navigation 3
• DI(Dependency Injection): Koin
• Networking: Ktor Client, Socket.IO Java-based SDK for Web Sockets
• Local Storage: Room Database and Jetpack DataStore

Backend

Please refer to the backend repository here: https://github.com/rohit9625/cross-chat-backend

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️️⚙️ Setup & Installation for Running Locally

Prerequisites

• Android Studio (latest version preferred)
• JDK 17 or higher
• Android SDK 34+ (Target SDK 36)

Setup

1. Clone the repository:

   git clone https://github.com/androhit/cross-chat.git
   cd cross-chat

2. Backend Configuration: The app is pre-configured to connect to a hosted backend. If you wish to use a local backend, update the BASE_URL in app/build.gradle.kts:

   buildTypes {
       debug {
           buildConfigField("String", "BASE_URL", "\"http://YOUR_LOCAL_IP:PORT\"")
       }
   }

   Note: Please check out the cross-chat-backend for running backend server locally.

3. Build the project:

   • Open the project in Android Studio.
   • Sync the project with Gradle files.
   • Build the project using Build > Make Project.

4. Run the app:

   • Select an emulator or a physical device.
   • Click the Run button.

🏗 Project Architecture

The project is structured into several modules/directories based on features:

• auth: Authentication code lives here
• chat: Chats and messages related code
• profile: Managing user preferences/settings

Each of the above modules is further divided into:

• data: Implementation of repositories, local (Room), and remote (Ktor/Socket.io) data sources.
• domain: Core business logic, repository interfaces, and models.
• ui: Jetpack Compose screens, ViewModels, and UI state management.

Apart from that, we have some root-level modules that share the logic across different feature modules

• navigation: Application flow control using Navigation 3.
• di: Dependency injection setup using Koin
• designsystem: Reusable UI components and theme definitions.

Note: The above architecture pattern follows the official Android guidelines and best practices

🤝 Contributing

Contributions are always welcome. But, please contact me before forking or creating a PR :)

Developed with pure dedication by Rohit Verma