Chat SDK is a fully featured open source instant messaging framework for iOS. Chat SDK is fully featured, scalable and flexible and follows the following key principles:

  • Open Source. The Chat SDK is open source and free for commerical apps (see license)
  • Full data control. You have full and exclusive access to the user's chat data
  • Quick integration. Chat SDK is fully featured out of the box
  • Firebase Powered by Google Firebase


Full breakdown is available on the features page.

Hire us to build your next app

We are now taking on projects, we are a team of full stack developers who are Firebase experts. For more information check out our consulting site.

Quick Start


You can test the XMPP Chat SDK on the App Store

Performance and Scalability

These are the average Firebase hosting costs calculated using the Firebase Database Profiling tool. Firebase charge 1 USD per GB of data downloaded (excluding images or files). We've tabulated a few common operations and how many of them can be performed per 1 USD of monthly hosting cost:

  • Messages Received (1kb) = 1,000,000
  • Logins (10kb) = 100,000
  • Profile Update (0.2kb) = 5,000,000
  • User search (2kb) = 500,000

What's possible on the Firebase free plan (10GB / month):

500k logins, 5 million messages.

What's possible on the Flame plan (20GB / month / 20 USD):

1 million logins, 10 million messages.

The real-time database will support up to 100k concurrent users. From our experience, 1 concurrent connection is enough to support 10 users per minute. That means that at peak capacity, the Chat SDK could support 1 million users per minute and well over 20 million monthly users.


Firebase Firestore

If you are interested in a version of the Chat SDK that supports Firebase's new database please vote on this issue and help us meet our target on Patreon.

Support the project

We would love to work full time developing the open source. At the moment we have to spend a substantial amount of time doing other consulting work to cover our costs. If you like what we're doing and would like to support us to focus more of our time on the open source project we would be very grateful.

Get involved!

We're very excited about the project and we're looking for other people to get involved. Over time we would like to make the best messaging framework for mobile. Helping us could involve any of the following:

  • Providing feedback and feature requests
  • Reporting bugs
  • Fixing bugs
  • Writing documentation
  • Improving the user interface
  • Help us update the library to use Swift
  • Helping to write adapters for other services such as Layer, Pusher, Pubnub etc...
  • Write a tutorial - we pay $100 for quality tutorials

If you're interested please review the Contributing Document for details of our development flow and the CLA then email me at

Apps that use Chat SDK

Here are the apps we know about that are using Chat SDK. If you've relased an app that uses the framework let us know and we'll add it to the list:

Setup Service and consulting

Setup Service

We provide extensive documentation on Github but if you’re a non-technical user or want to save yourself some work you can take advantage of our setup and integration service.

Consulting services

We are specialists in real-time application development including: Firebase, Firestore, XMPP and WebRTC for iOS and Android. If you need help integrating the Chat SDK with your app or another app development project email us at [](mailto:

Updating from 4.10.x to 4.11.x

The latest update brings a range of improvements and new features including:

  • Detailed profile screen:
    • User status
    • User availability
    • Country
  • Update to message view
    • Vastly improved lazy loading
    • Efficiency improvements
  • Contacts
    • Add / remove contact from contact screen

There are also a range of bug fixes and overall improvments. If we aren't able to document all the changes but if you have any issues updating your project, you can post on this issue and we will answer your questions.

The security rules have also been updated so make sure to bring your project up to date.

Update the CoreData model

Make sure that the CoreData model is the latest version. This model lives in ChatSDK/CoreData/Resources/ChatSDK.xcdatamodelId

Several schema have also been deprecated and will be removed at some point in the future. These include:

  • message/to field added
  • message/meta will replace json_v2
  • message/from will replace user-firebase-id
  • thread/meta will replace details
  • thread/meta/creator will replace creator-entity-id
  • thread/meta/type will replace type_v4

At the moment these fields are not being used and are only included for future compatibility. However, in a future version of the client, the old fields will be removed and any old versions of the client will stop working.

Running the demo project

This repository contains a fully functional version of the Chat SDK which is configured using our Firebase account. This is great way to test the features of the Chat SDK before you start itegrating it with your app.

  1. Clone Chat SDK
  2. Run pod install in the Xcode directory
  3. Open the Chat SDK Firebase.xcworkspace file in Xcode
  4. Compile and run

Swift Version

The Chat SDK is fully compatible with Swift projects and contains a Swift demo project.

  1. Clone Chat SDK
  2. Run pod install in the XcodeSwift directory
  3. Open the ChatSDKSwift.xcworkspace file in Xcode
  4. Compile and run

Adding the Chat SDK to your project

Quick start guide - it takes about 10 minutes!

Adding the Chat SDK to your project

  1. Add the Chat SDK development pods to your Podfile

    pod "ChatSDK"
    pod "ChatSDKFirebase/Adapter"
    pod "ChatSDKFirebase/FileStorage"
    pod "ChatSDKFirebase/Push"
  2. Run pod update to get the latest version of the code.

  3. Open the App Delegate add the following code to initialise the chat

    Objective C

    AppDelegate.m -> application: didFinishLaunchingWithOptions:

    #import <ChatSDK/UI.h>

    Add the following code to the start of your didFinishLaunchingWithOptions function:

    BConfiguration * config = [BConfiguration configuration];
    config.rootPath = @"test";
    // Configure other options here...
    [BChatSDK initialize:config app:application options:launchOptions];
    // Set the root view controller
    [self.window setRootViewController:BChatSDK.ui.splashScreenNavigationController];

    Then add the following methods:

    - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
      return [BChatSDK application:application openURL:url sourceApplication:sourceApplication annotation:annotation];
    -(BOOL) application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options {
      return [BChatSDK application: app openURL: url options: options];
    -(void) application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken {
      [BChatSDK application:application didRegisterForRemoteNotificationsWithDeviceToken:deviceToken];
    -(void) application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {
      [BChatSDK application:application didReceiveRemoteNotification:userInfo];



    import ChatSDK

    Add the following code to the start of your didFinishLaunchingWithOptions function:

    let config = BConfiguration.init();
    config.rootPath = "test"
    // Configure other options here...
    config.allowUsersToCreatePublicChats = true
    BChatSDK.initialize(config, app: application, options: launchOptions)
    self.window = UIWindow.init(frame: UIScreen.main.bounds)
    self.window?.rootViewController = BChatSDK.ui()?.splashScreenNavigationController()

    Then add the following methods:

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        BChatSDK.application(application, didRegisterForRemoteNotificationsWithDeviceToken: deviceToken)
    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        BChatSDK.application(application, didReceiveRemoteNotification: userInfo)
    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
        BChatSDK.application(application, didReceiveRemoteNotification: userInfo)
    func application(_ application: UIApplication, open url: URL, sourceApplication: String?, annotation: Any) -> Bool {
        return BChatSDK.application(application, open: url, sourceApplication: sourceApplication, annotation: annotation)
    func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
        return BChatSDK.application(app, open: url, options: options)
    The Root Path

    The root path variable allows you to run multiple Chat SDK instances on one Firebase account. Each different root path will represent a completely separate set of Firebase data. This can be useful for testing because you could have separate test and prod root paths.

  4. The Chat SDK is now added to your project

Firebase Setup

  1. Go to the Firebase website and sign up
  2. Go to the Firebase console and make a new project
  3. Click Add project
  4. Choose a name and a location
  5. Click Settings (the gear icon). On the General tab, click Add Firebase to your iOS app
  6. Enter your bundle ID
  7. Download the GoogleServices file and add it to the root of your Xcode project

    It is worth opening your downloaded GoogleService-Info.plist and checking there is an API_KEY field included. Sometimes Firebase's automatic download doesn’t include this in the plist. To rectify, just re-download the plist from the project settings menu.

  8. Copy the following rows from the demo ChatSDK Info.plist file to your project's Info.plist

    1. App Transport Security Settings
    2. URL types
    3. Make sure that the URL types are all set correctly. The URL type for your app should be set to your bundle id
    4. All the privacy rows. These will allow the app to access the camera, location and address book
  9. In the Firebase dashboard click Authentication -> Sign-in method and enable all the appropriate methods

  10. Add the security rules. The rules also enable optimized user search so this step is very important!
  11. Enable file storage - Click Storage -> Get Started
  12. Enable push notifications
  13. Enable location messages. Get a Google Maps API key. Then add it during the Chat SDK configuration

    Objective C

    config.googleMapsApiKey = @"YOUR API KEY";


    config.googleMapsApiKey = "YOUR API KEY"

Push Notifications

The Push Notification module allows you to send free push notifications using Firebase Cloud Messaging.

  1. Setup an APN key.
  2. Inside your project in the Firebase console, select the gear icon, select Project Settings, and then select the Cloud Messaging tab.
  3. In APNs authentication key under iOS app configuration, click the Upload button.
  4. Browse to the location where you saved your key, select it, and click Open. Add the key ID for the key (available in Certificates, Identifiers & Profiles in the Apple Developer Member Center) and click Upload.
  5. Enable the push notifications Capability in your Xcode project Project -> Capabilities -> Push Notifications
  6. In Xcode open the Capabilities tab. Enable Push Notifications and the following Background Modes: Location updates, Background fetch, Remote notifications.
Setup Firebase Cloud Functions

Follow the instructions on our Chat SDK Firebase repository

Security Rules

Firebase secures your data by allowing you to write rules to govern who can access the database and what can be written. The rules are also needed to enable user search. To enable the rules see the guide Enabling Security Rules.


Congratulations! 🎉🎉 You've just turned your app into a fully featured instant messenger! Keep reading below to learn how to further customize the Chat SDK.

To go deeper, checkout the API Guide for help with:
  1. Interacting with the Firebase server
  2. Creating and updating entities
  3. Custom authentication
  4. Common code examples
  5. Customizing the user interface

View the API documentation here.

Next Steps


There are a number of configuration options available. Check out the BConfiguration class. Using this class you can do things like:

  • Changing the chat bubble colors
  • Changing the default user name
  • Enable or disable different types of login
  • Show or hide empty chats
  • etc...

Customize the UI

To customize the UI, you can register subclasses for different views. You can do that using the UI service BChatSDK.ui. For example, to register a new login view controller you would use:

BChatSDK.ui.loginViewController = [[YourViewController alloc] initWithNibName:Nil bundle: Nil];

To modify the chat view you would register a provider:

[BChatSDK.ui setChatViewController:^BChatViewController *(id<PThread> thread) {
        return [[YourChatViewController alloc] initWithThread:thread];

Every view controller in the app can be customized this way.

Use Chat SDK views in your app

Any of the Chat SDK views can be added into your app. Checkout the PInterfaceFacade for options. You can add a any view using the following pattern. Here we are using the interface service to get the particular view.


UIViewController * privateThreadsViewController = [BChatSDK.ui privateThreadsViewController];


let privateThreadsViewController = BChatSDK.ui().a.privateThreadsViewController()

Integrate the Chat SDK with your existing app

To do that, you can take advantage of the BIntegrationHelper class. This makes provides some helper methods to make it easier to integrate the Chat SDK with your app.

At the most basic level, you need to do the following:

  1. Authenticate the Chat SDK when your app authenticates. The best way to do this is to generate a custom token on your server following this guide. Then use this method to initialize the Chat SDK:


    [BIntegrationHelper authenticateWithToken:@"your token"];


    BIntegrationHelper.authenticate(withToken: "your token")
  2. Update the Chat SDK user's name and image whenever your user's name or image changes. You can do this using the following method:


    [BIntegrationHelper updateUserWithName:@"Name" image: image url: imageURL];


    BIntegrationHelper.updateUser(withName: "Name", image: image, url: imageURL)
  3. Logout of the Chat SDK whenever your app logs out. A good place to do this is whenever your login screen is displayed:


    [BIntegrationHelper logout];


  4. Now the Chat SDK is integrated with your app.

Module Setup

There are a number of free and premium extensions that can be added to the Chat SDK.

Firebase Modules

For the following modules:

The free modules are located in the chat-sdk-ios/ChatSDKFirebase folder. The premium modules can be purchased and downloaded from the links provided above.

To install a module you should use the following steps:

  1. Copy the module code into your Xcode source code folder and add the files to your project from inside Xcode. If you are using a symlink you can use the symlink script (mentioned above) and then just add a link to the ChatSDKFirebase folder to Xcode.
  2. Add any necessary dependencies to your Podfile
  3. As soon as you add the module code, it will be detected and installed automatically by the Chat SDK.

Firebase UI

The File UI module allows you to use the native Firebase user interface for authentication.

After adding the files to your Xcode project, add the following to the App Delegate to enable the module.

Objective C

AppDelegate.m -> application: didFinishLaunchingWithOptions:

 #import "BFirebaseUIModule.h"

[[[BFirebaseUIModule alloc] init] activateWithProviders: @[]];



 #import "BFirebaseUIModule.h"


BFirebaseUIModule.init().activate(withProviders: []);

You should pass in array of the FUIAuthProvider objects you want to support.

Also add the following to your Podfile depending on which authentication methods you want to support:

pod 'FirebaseUI/Facebook', '~> 4.0'
pod 'FirebaseUI/Google', '~> 4.0'
pod 'FirebaseUI/Twitter', '~> 4.0'
pod 'FirebaseUI/Phone', '~> 4.0'

Then run pod install.

Note If you want to Firebase Auth UI make sure you comment out the following line:

BNetworkManager.shared().a.auth().setChallenge(BLoginViewController.init(nibName: nil, bundle: nil));

Other Modules

For the following modules:

These modules are distributed as development pods. After you've downloaded the module, unzip it and add it to the ChatSDKModules folder. Then:

  1. Open your Podfile
  2. Add the line:

    pod "ChatSDKModules/[ModuleName]", :path => "[Path to ChatSDKModules folder]"
  3. Run pod install
  4. The module is now active

Using the Chat SDK API

The Chat SDK API is based around the network manager and a series of handlers. A good place to start is by looking at the handlers Pods/Development Pods/ChatSDK/Core/Core/Classes/Interfaces. Here you can review the handler interfaces which are well documented. To use a handler you would use the following code:

Objective C

[[BChatSDK.handler_name function: to: call:]


BNetworkManager.shared().a.handler_name() function: to: call:]
Searching for a user

For example, to search for a user you could use the search handler:

-(RXPromise *) usersForIndexes: (NSArray *) indexes withValue: (NSString *) value limit: (int) limit userAdded: (void(^)(id<PUser> user)) userAdded;

Here you pass in a series of indexes to be used in the search i.e. name, email etc... and a value. It will then return a series of user objects.

You can also see example implementations of these handlers by looking at the BFirebaseSearchHandler class. And also seeing how the method is used in the Chat SDK.

Starting a chat

To start a chat you can use the core handler.

-(RXPromise *) createThreadWithUsers: (NSArray *) users
                       threadCreated: (void(^)(NSError * error, id<PThread> thread)) thread;

When this method completes, the thread will have been created on Firebase and all the users will have been added. You could then open the thread using the interface adapter.

UIViewController * chatViewController = [BChatSDK.ui chatViewControllerWithThread:thread];

So a more complete example would look like this:

-(void) startChatWithUser {
    MBProgressHUD * hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    hud.label.text = [NSBundle t:bCreatingThread];

    [[BChatSDK.core createThreadWithUsers:@[_user] threadCreated:^(NSError * error, id<PThread> thread) {
        if (!error) {
            [self pushChatViewControllerWithThread:thread];
        else {
            [UIView alertWithTitle:[NSBundle t:bErrorTitle] withMessage:[NSBundle t:bThreadCreationError]];
        [MBProgressHUD hideHUDForView:self.view animated:YES];

-(void) pushChatViewControllerWithThread: (id<PThread>) thread {
    if (thread) {
        UIViewController * chatViewController = [BChatSDK.ui chatViewControllerWithThread:thread];
        [self.navigationController pushViewController:chatViewController animated:YES];

Troubleshooting Cocoapods

  1. Always open the .xcworkspace file rather than .xcodeproj
  2. Check CocoaPod warnings - make sure to fix any warnings before proceeding
  3. Make sure that your base configuration isn’t set: Project -> project name -> Info -> Configuration
  4. Make sure that the “Build Active Architecture Only” setting is the same for both the main project and the pods project.
  5. Check the build settings in the Xcode project and check which fields are in bold (this means that their value has been overridden and CocoaPods can't access them). If you press backspace while selecting those fields, their values will be set to the default value.

The license

We offer a choice of two license for this app. You can either use the Chat SDK license or the GPLv3 license.

Most Chat SDK users either want to add the Chat SDK to an app that will be released to the App Store or they want to use the Chat SDK in a project for their client. The Chat SDK license gives you complete flexibility to do this for free.

Chat SDK License Summary

  • License does not expire.
  • Can be used for creating unlimited applications
  • Can be distributed in binary or object form only
  • Commercial use allowed
  • Can modify source-code but cannot distribute modifications (derivative works)

If a user wants to distribute the Chat SDK source code, we feel that any additions or modifications they make to the code should be contributed back to the project. The GPLv3 license ensures that if source code is distributed, it must remain open source and available to the community.

GPLv3 License Summary

  • Can modify and distribute source code
  • Commerical use allowed
  • Cannot sublicense or hold liable
  • Must include original license
  • Must disclose source

What does this mean?

Please check out the Licensing FAQ for more information.