Implement First Call

CallKit is built upon the CallLib SDK foundation, providing a default call interface that supports various scenarios and functionalities for one-to-one and multi-party audio/video calls.

tip

Room Capacity Limits

Considering mobile device bandwidth (especially in multi-party video scenarios) and UI interaction effects, we recommend limiting video participants to 16 and audio-only participants to 32 per call/room. Exceeding these limits may impact call quality.
CallKit has preset participant limits: up to 7 users for video calls and 20 for audio calls by default. To adjust these limits, modify the maxMultiVideoCallUserNumber and maxMultiAudioCallUserNumber parameters in RCCall, but avoid exceeding recommended thresholds.

Environment Requirements

Minimum requirements for CallKit SDK on iOS:

iOS 9.0 or later
Xcode 9.0 or later

Prerequisites

Create a RC developer account to obtain your App Key. Upon registration, RC Console automatically creates your first application with a development environment App Key using the China (Beijing) Data Center. Note: The development and production environments of the same app have separate App Keys and isolated data.
Complete RTC service activation. You need to enable the RTC service.

Demo Project

RC provides an iOS demo project showcasing call, meeting, and live streaming functionalities:

https://github.com/rongcloud/rtc-quickdemo-ios

Before running QuickDemo, ensure you've completed:

Registered an RC developer account
Prepared your App Key
Activated the RTC free trial and waited 15 minutes
Obtained a test Token.

Get Source Code

CallKit is open-source. You can review or integrate the code to customize UI elements like color schemes and button layouts.

https://github.com/rongcloud/callkit-ios/

Dependency Notes

IMLib (green) exists as a framework within RongCloudIM
RTCLib and CallLib (yellow) exist as frameworks within RongCloudRTC
IMKit, its plugins, and CallKit (white) can exist as source code, exclusively in RongCloudOpenSource

White components may have corresponding frameworks, but in your project they must all be either source code or frameworks to avoid conflicts.

Implementation Recommendations

For source code customization:

Avoid direct source modification to prevent upgrade conflicts
Extend functionality by subclassing and overriding methods rather than modifying originals
Use only public SDK interfaces—private APIs may change during updates

Quick Start

Step 1: Import SDK

RC supports CocoaPods and manual framework integration.

Check the RC SDK download page for the latest version before importing.

CocoaPods

Choose between framework or source code integration via CocoaPods.

tip

When using CallKit with IMKit and plugins, never mix frameworks and source code. See SDK Open Source Notes.

Framework Integration

Add to Podfile:
```
pod 'RongCloudRTC/RongCallKit', '~> x.y.z'
```
Replace x.y.z with the version number (check RC download page or CocoaPods).
Run:
```
pod install
```
If version errors occur, run pod repo update first.
This generates an .xcworkspace file—open it with Xcode.

Source Code Integration

CallKit SDK 5.1.9+ supports source-level debugging via CocoaPods.

Add to Podfile as needed:

pod 'RongCloudRTCOpenSource/RongCallKit','x.x.x'    # RongCallKit

Run:
```
pod install
```
For version errors, run pod repo update first.
Open the generated .xcworkspace with Xcode.
Reference libraries with:
```
#import <RongCallKit.h>
```

Manual Framework Integration

Before importing, visit the RC SDK download page to download the RTC SDK (no UI).

tip

From v5.2.0 to 5.4.4 (exclusive), CallKit/CallLib/RTCLib must match IMKit/IMLib versions exactly (first three digits). Starting with 5.4.4, only the first two version digits need to match. CallKit/CallLib/RTCLib 5.4.4 cannot pair with IMKit/IMLib versions below 5.4.4.

Import RongCallKit.xcframework with Embed & Sign
Import RongCallLib.xcframework with Embed & Sign
Import RongRTCLib.xcframework with Embed & Sign
Import RongIMLib.xcframework with Embed & Sign
Import RongIMKit.xcframework with Embed & Sign
Import RongIMLibCore.xcframework with Embed & Sign

Step 2: Project Configuration

Add these keys to info.plist for microphone/camera permissions:
- Privacy - Microphone Usage Description
- Privacy - Camera Usage Description
Enable these Background Modes under Target -> Signing & Capabilities:
- Audio, AirPlay, and Picture in Picture
- Remote notifications

tip

For SDK versions ≤5.1.1, add App Transport Security Settings with Allow Arbitrary Loads set to YES in info.plist to permit HTTP requests.

Step 3: Initialization

Since RTC SDK uses IM SDK as its signaling channel, initialize IM SDK first. Do this once during app lifecycle, ideally at launch or when loading RTC features.

// Initialize IM SDK
[[RCIM sharedRCIM] initWithAppKey:@"Get AppKey from developer platform"];

Step 4: Connect to IM Service

RTC signaling relies on RC's IM service. Establish a TCP connection via connectWithToken before making calls. Call disconnect or logout when exiting the module.

[[RCIM sharedRCIM] connectWithToken:@"Token from your server"
                           dbOpened:^(RCDBErrorCode code) {
                               if (code != RCDBErrorCode_Success) {
                                   // Handle database open failure
                               }
                           }
                            success:^(NSString *userId) {
                               // Handle connection success
                           }
                              error:^(RCConnectErrorCode status) {
                               // Handle connection failure
                           }];

Step 5: Caller Implementation

Apps typically need both calling and receiving logic.

Initiate 1:1 Call

- (void)startSingleCall:(NSString *)targetId mediaType:(RCCallMediaType)mediaType;

Parameter	Type	Required	Description
targetId	NSString	Yes	Callee's user ID
mediaType	RCCallMediaType	Yes	Media type

Example:

[[RCCall sharedRCCall] startSingleCall:@"CalleeUserId" mediaType:RCCallMediaVideo];

Initiate Group Call

Group calls require either ConversationType_GROUP or ConversationType_DISCUSSION, with all participants in the same group.

- (void)startMultiCallViewController:(RCConversationType)conversationType
                            targetId:(NSString *)targetId
                           mediaType:(RCCallMediaType)mediaType
                          userIdList:(NSArray *)userIdList;

Parameters:

Parameter Type Required Description
conversationType RCConversationType Yes Conversation type
targetId NSString Yes Group ID
mediaType RCCallMediaType Yes Media type
userIdList NSArray Yes Callee user ID list

Parameter	Type	Required	Description
conversationType	RCConversationType	Yes	Conversation type
targetId	NSString	Yes	Group ID
mediaType	RCCallMediaType	Yes	Media type
userIdList	NSArray	Yes	Callee user ID list

Example:

[[RCCall sharedRCCall] startMultiCallViewController:ConversationType_GROUP
                                           targetId:@"GroupID"
                                          mediaType:RCCallMediaVideo
                                         userIdList:@[@"UserA", @"UserB", @"UserC"]];

Member Selection Call

This method first shows a member selection UI before initiating a group call. For group calls, implement groupMemberDataSource.

- (void)startMultiCall:(RCConversationType)conversationType
              targetId:(NSString *)targetId
             mediaType:(RCCallMediaType)mediaType;

Parameters:

Parameter Type Required Description
conversationType RCConversationType Yes Conversation type
targetId NSString Yes Group ID
mediaType RCCallMediaType Yes Media type

Parameter	Type	Required	Description
conversationType	RCConversationType	Yes	Conversation type
targetId	NSString	Yes	Group ID
mediaType	RCCallMediaType	Yes	Media type

Example:

[[RCCall sharedRCCall] startMultiCall:ConversationType_GROUP
                             targetId:@"GroupID"
                            mediaType:RCCallMediaVideo];

Step 6: Callee Implementation

CallKit implements RCCallReceiveDelegate (incoming call handling) and RCCallSessionDelegate (call status) from CallLib. When receiving a call, the interface auto-launches—simply tap "Answer" to join.

If the app is backgrounded/closed, users receive a notification. Tapping it launches the app with the call interface.

Plugin Integration

CallKit supports official beauty filters or FaceUnity plugins. Note: FaceUnity requires CallKit ≥5.4.0.

IMLib

IMKit

Global Chat UIKit

push notification

IMLib

Global Chat UIKit

CallLib

CallKit

RTCLib

Chat Server

Chat Server SDK

Audio & Video Server

Environment Requirements​

Prerequisites​

Demo Project​

Get Source Code​

Dependency Notes​

Implementation Recommendations​

Quick Start​

Step 1: Import SDK​

CocoaPods​

Framework Integration​

Source Code Integration​

Manual Framework Integration​

Step 2: Project Configuration​

Step 3: Initialization​

Step 4: Connect to IM Service​

Step 5: Caller Implementation​

Initiate 1:1 Call​

Initiate Group Call​

Member Selection Call​

Step 6: Callee Implementation​

Plugin Integration​

Customization​

Environment Requirements

Prerequisites

Demo Project

Get Source Code

Dependency Notes

Implementation Recommendations

Quick Start

Step 1: Import SDK

CocoaPods

Framework Integration

Source Code Integration

Manual Framework Integration

Step 2: Project Configuration

Step 3: Initialization

Step 4: Connect to IM Service

Step 5: Caller Implementation

Initiate 1:1 Call

Initiate Group Call

Member Selection Call

Step 6: Callee Implementation

Plugin Integration

Customization