IVS Broadcast SDK: Token Exchange | Real-Time Streaming

Token exchange enables you to upgrade or downgrade participant-token capabilities and update token attributes within the mobile broadcast SDK, without requiring participants to reconnect. This is useful for scenarios like co-hosting, where participants may start with subscribe-only capabilities and later need publish capabilities.

Limitations:

Exchanging Tokens

Exchanging tokens is straightforward: call the exchangeToken API on the Stage / IVSStage object and provide the new token. If the capabilities of the new token are different than those of the previous token, the new token's capabilities are evaluated immediately. For example, if the previous token did not have the publish capability and the new token does, the stage strategy functions for publishing are invoked, allowing the host application to decide if they want to publish right away with the new capability, or wait. The same is true for removed capabilities: if the previous token had the publish capability and the new token does not, the participant immediately unpublishes without invoking the stage strategy functions for publishing.

When exchanging a token, the previous and new token must have the same values for the following payload fields:

These fields are immutable. Exchanging a token that modifies an immutable field results in the SDK immediately rejecting the exchange.

The remaining fields can be changed, including:

iOS

let stage = try IVSStage(token: originalToken, strategy: self)
stage.join()
stage.exchangeToken(newToken)

Android

val stage = Stage(context, originalToken, strategy)
stage.join()
stage.exchangeToken(newToken)

Receiving Updates

A function in StageRenderer / IVSStageRenderer receives updates about already-published, remote participants that exchange their tokens to update their userId or attributes. Remote participants that are not already publishing will have their updated userId and attributes exposed via the existing onParticipantJoined / participantDidJoin renderer functions if they eventually publish.

iOS

class MyStageRenderer: NSObject, IVSStageRenderer {
    func stage(_ stage: IVSStage, participantMetadataDidUpdate participant: IVSParticipantInfo) {
        // participant will be a new IVSParticipantInfo instance with updated properties.
    }
}

Android

private val stageRenderer = object : StageRenderer {
    override fun onParticipantMetadataUpdated(stage: Stage, participantInfo: ParticipantInfo) {
        // participantInfo will be a new ParticipantInfo instance with updated properties.
    }
}

Visibility of Updates

When a participant exchanges a token to update their userId or attributes, the visibility of these changes depends on their current publishing state:

This table clarifies the matrix of support: