CLASS

`Call`

public class Call

A Call represents an audio or video communication session between two endpoints: WebRTC Clients, SIP clients, or phone numbers. The Call object manages the entire lifecycle of a call, from initiation to termination, handling both outbound and inbound calls. A Call object is created in two scenarios:

When you initiate a new outbound call using TxClient’s newCall method
When you receive an inbound call through the TxClientDelegate’s onIncomingCall callback

Key Features

Audio and video call support
Call state management (NEW, CONNECTING, RINGING, ACTIVE, HELD, DONE)
Mute/unmute functionality
DTMF tone sending
Custom headers support for both INVITE and ANSWER messages
Call statistics reporting when debug mode is enabled

Examples

Creating an Outbound Call:

   // Initialize the client
   self.telnyxClient = TxClient()
   self.telnyxClient?.delegate = self

   // Connect the client (see TxClient documentation for connection options)
   self.telnyxClient?.connect(....)

   // Create and initiate a call
   self.currentCall = try self.telnyxClient?.newCall(
       callerName: "John Doe",           // The name to display for the caller
       callerNumber: "155531234567",     // The caller's phone number
       destinationNumber: "18004377950", // The target phone number or SIP URI
       callId: UUID.init(),              // Unique identifier for the call
       clientState: nil,                 // Optional client state information
       customHeaders: [:]                // Optional custom SIP headers
   )

Handling an Incoming Call:

class CallHandler: TxClientDelegate {
    var activeCall: Call?

    func initTelnyxClient() {
        let client = TxClient()
        client.delegate = self
        client.connect(....)
    }

    func onIncomingCall(call: Call) {
        // Store the call reference
        self.activeCall = call

        // Option 1: Auto-answer the call
        call.answer()

        // Option 2: Answer with custom headers
        call.answer(customHeaders: ["X-Custom-Header": "Value"])

        // Option 3: Reject the call
        // call.hangup()
    }
}

Properties

`onCallQualityChange`

public var onCallQualityChange: ((CallQualityMetrics) -> Void)?

Callback for real-time call quality metrics This is triggered whenever new WebRTC statistics are available

`inviteCustomHeaders`

public internal(set) var inviteCustomHeaders: [String:String]?

Custom headers received from the WebRTC INVITE message. These headers are passed during call initiation and can contain application-specific information. Format should be [“X-Header-Name”: “Value”] where header names must start with “X-”.

`answerCustomHeaders`

public internal(set) var answerCustomHeaders: [String:String]?

Custom headers received from the WebRTC ANSWER message. These headers are passed during call acceptance and can contain application-specific information. Format should be [“X-Header-Name”: “Value”] where header names must start with “X-”.

`sessionId`

public internal(set) var sessionId: String?

The unique session identifier for the current WebRTC connection. This ID is established during client connection and remains constant for the session duration.

`telnyxSessionId`

public internal(set) var telnyxSessionId: UUID?

The unique Telnyx session identifier for this call. This ID can be used to track the call in Telnyx’s systems and logs.

`telnyxLegId`

public internal(set) var telnyxLegId: UUID?

The unique Telnyx leg identifier for this call. A call can have multiple legs (e.g., in call transfers). This ID identifies this specific leg.

`debug`

public internal(set) var debug: Bool = false

Enables WebRTC statistics reporting for debugging purposes. When true, the SDK will collect and send WebRTC statistics to Telnyx servers. This is useful for troubleshooting call quality issues.

`enableQualityMetrics`

public internal(set) var enableQualityMetrics: Bool = false

Enables CallQuality Metrics for Call

`sendWebRTCStatsViaSocket`

public internal(set) var sendWebRTCStatsViaSocket: Bool = false

Controls whether the SDK should send WebRTC statistics via socket to Telnyx servers. When enabled, collected WebRTC stats will be sent to Telnyx servers for monitoring and debugging. This is independent of stats collection - stats can be collected without being sent via socket.

`useTrickleIce`

public internal(set) var useTrickleIce: Bool = false

Controls whether the SDK should use trickle ICE for WebRTC signaling. When enabled, ICE candidates are sent individually as they are discovered, rather than waiting for all candidates to be gathered before sending the offer/answer.

`forceRelayCandidate`

public internal(set) var forceRelayCandidate: Bool = false

Controls whether the SDK should force TURN relay for peer connections. When enabled, the SDK will only use TURN relay candidates for ICE gathering, which prevents the “local network access” permission popup from appearing.

`enableCallReports`

public internal(set) var enableCallReports: Bool = true

Enable automatic call quality reporting to voice-sdk-proxy. When enabled, WebRTC stats are collected periodically during calls and posted to the voice-sdk-proxy /call_report endpoint when the call ends.

`callReportInterval`

public internal(set) var callReportInterval: TimeInterval = 5.0

Interval in seconds for collecting call statistics. Stats are aggregated over each interval and stored locally until call end.

`callReportLogLevel`

public internal(set) var callReportLogLevel: String = "debug"

Minimum log level to capture for call reports (“debug”, “info”, “warn”, “error”).

`callReportMaxLogEntries`

public internal(set) var callReportMaxLogEntries: Int = 1000

Maximum number of log entries to buffer per call.

`callInfo`

public var callInfo: TxCallInfo?

Contains essential information about the current call including:

callId: Unique identifier for this call
callerName: Display name of the caller
callerNumber: Phone number or SIP URI of the caller See TxCallInfo for complete details.

`callState`

public var callState: CallState = .NEW

The current state of the call. Possible values:

NEW: Call object created but not yet initiated
CONNECTING: Outbound call is being established
RINGING: Incoming call waiting to be answered
ACTIVE: Call is connected and media is flowing
HELD: Call is temporarily suspended
DONE: Call has ended

The state changes are notified through the CallProtocol delegate.

`isMuted`

public var isMuted: Bool

Indicates whether the local audio is currently muted.

Returns: true if the call is muted (audio track disabled)
Returns: false if the call is not muted (audio track enabled)

Use muteAudio() and unmuteAudio() to change the mute state.

`localStream`

public var localStream: RTCMediaStream?

The local media stream containing audio and/or video tracks being sent to the remote party. This stream represents the media captured from the local device (microphone, camera). Can be used for audio visualization, local video preview, or other media processing.

Examples

// Access local audio tracks for visualization
if let localStream = call.localStream {
    let audioTracks = localStream.audioTracks
    // Use audio tracks for waveform visualization
}

`remoteStream`

public var remoteStream: RTCMediaStream?

The remote media stream containing audio and/or video tracks received from the remote party. This stream represents the media being received from the other participant in the call. Can be used for audio visualization, remote video display, or other media processing.

Examples

// Access remote audio tracks for visualization
if let remoteStream = call.remoteStream {
    let audioTracks = remoteStream.audioTracks
    // Use audio tracks for waveform visualization
}

Getting Started

Authentication

Push Notifications

Tutorials

Use Cases

Troubleshooting

SDKs

API Reference

For AI Agents

WebRTC iOS Call

`Call`

Key Features

Examples

Creating an Outbound Call:

Handling an Incoming Call:

Properties

`onCallQualityChange`

`inviteCustomHeaders`

`answerCustomHeaders`

`sessionId`

`telnyxSessionId`

`telnyxLegId`

`debug`

`enableQualityMetrics`

`sendWebRTCStatsViaSocket`

`useTrickleIce`

`forceRelayCandidate`

`enableCallReports`

`callReportInterval`

`callReportLogLevel`

`callReportMaxLogEntries`

`callInfo`

`callState`

`isMuted`

`localStream`

Examples

`remoteStream`

Examples

​Call

​Key Features

​Examples

​Creating an Outbound Call:

​Handling an Incoming Call:

​Properties

​onCallQualityChange

​inviteCustomHeaders

​answerCustomHeaders

​sessionId

​telnyxSessionId

​telnyxLegId

​debug

​enableQualityMetrics

​sendWebRTCStatsViaSocket

​useTrickleIce

​forceRelayCandidate

​enableCallReports

​callReportInterval

​callReportLogLevel

​callReportMaxLogEntries

​callInfo

​callState

​isMuted

​localStream

​Examples

​remoteStream

​Examples

`Call`

Key Features

Examples

Creating an Outbound Call:

Handling an Incoming Call:

Properties

`onCallQualityChange`

`inviteCustomHeaders`

`answerCustomHeaders`

`sessionId`

`telnyxSessionId`

`telnyxLegId`

`debug`

`enableQualityMetrics`

`sendWebRTCStatsViaSocket`

`useTrickleIce`

`forceRelayCandidate`

`enableCallReports`

`callReportInterval`

`callReportLogLevel`

`callReportMaxLogEntries`

`callInfo`

`callState`

`isMuted`

`localStream`

Examples

`remoteStream`

Examples