Interface IClientOptions

anonymous_login login options

Enable debug mode for this client. This will gather WebRTC debugging information.

Debug output option

Environment to use for the connection. So far this property is only for internal purposes.

Force the use of a relay ICE candidate.

ICE Servers to use for all calls within the client connection. Overrides the default ones.

Optimistic flag to attempt keeping the call alive when the WebSocket connection closes.

When enabled, the SDK will attempt to preserve the active call during brief network interruptions (e.g., network offline, switching networks, device sleep/wake cycles) by re-attaching to the existing peer connection instead of hanging up when an attach message is received.

Important: This is an optimistic setting, not a deterministic guarantee. Recovery depends on the state of the underlying WebRTC peer connection:

• Recovery succeeds when:

  • The peer connection's signalingState is NOT closed
  • The peer connection instance still exists
  • ICE restart was not triggered due to connection failure

• Recovery fails (call will be hung up and recreated) when:

  • The peer connection's connectionState transitions to failed
  • The peer connection's signalingState transitions to closed (e.g., after device sleep)
  • The peer connection instance was destroyed

Fallback Behavior: When recovery is not possible, the SDK automatically falls back to recreating the call. The fallback process depends on the failure scenario:

1. If ICE restart was attempted (connectionState went to failed):

   • The SDK hangs up the existing call and sends a BYE message
   • A new call instance is created with a new call ID
   • The SDK sends a new INVITE to re-establish the call as the active leg

2. For all other unrecoverable states (signalingState closed, peer destroyed):

   • The SDK hangs up the existing call (no BYE sent since connection is dead)
   • A new call instance is created with the same call ID
   • The SDK answers the incoming ATTACH to re-establish the call

Monitoring Connection Health: Subscribe to these events to detect connection issues:

• telnyx.rtc.peerConnectionFailureError - Primary event. Fires when connectionState goes to failed. This indicates the ICE/DTLS transport failed and recovery will be attempted via ICE restart.

• telnyx.rtc.peerConnectionSignalingStateClosed - Fires when signalingState transitions to closed. Check call.signalingStateClosed to verify recoverability.

In both cases, if autoRecoverCalls is enabled (default: true), the fallback is automatic and seamless. The call's state transitions through the normal flow and a callUpdate notification is dispatched so your UI can update accordingly.

See

Error Handling Documentation

The username to authenticate with your SIP Connection. login and password will take precedence over login_token for authentication.

The JSON Web Token (JWT) to authenticate with your SIP Connection. This is the recommended authentication strategy. See how to create one.

Disabled microphone by default when the call starts or adding a new audio source.

The password to authenticate with your SIP Connection.

Enable or disable prefetching ICE candidates.

Region to use for the connection.

A URL to a wav/mp3 ringback file that will be used when you disable "Generate Ringback Tone" in your SIP Connection.

A URL to a wav/mp3 ringtone file.

RTC connection IP address to use instead of the default one. Useful when using a custom signaling server.

RTC connection port to use instead of the default one. Useful when using a custom signaling server.

Enable or disable Trickle ICE.

Use Telnyx's Canary RTC server