Definition

Activating the audio session means enabling the app’s configured audio behavior so voice communication can begin.

In CallKit apps, audio activation is coordinated by the system through:

provider(
    _ provider: CXProvider,
    didActivate audioSession: AVAudioSession
)

Core Concept

Your app should not immediately start audio when:

• the call starts
• the user taps answer
• the outgoing request is sent

Instead, the app should wait until CallKit says:

“The system audio session is now active and ready.”

Why This Exists

iOS centrally coordinates:

• telephony audio
• Bluetooth routing
• AirPods
• speaker behavior
• interruptions