Connection keepalive

Overview

In real-time transcription, you may have periods of silence — for example when using
client-side VAD (voice activity detection), during pauses in speech, or when you intentionally stop streaming audio.

To keep the session alive and preserve context, you must send a keepalive control message:

{"type": "keepalive"}

This prevents the WebSocket connection from timing out when no audio is being sent.

When to use

Send a keepalive message whenever:

• You only stream audio during speech (client-side VAD).
• You temporarily pause audio streaming but want to keep the session active.

This ensures that:

• The connection stays open.
• Session context (e.g., speaker labels, language tracking, prompt) is preserved.

Key points

• Send at least once every 20 seconds when not sending audio.
• You may send more frequently (every 5–10s is common).
• If no keepalive or audio is received for >20s, the connection may be closed.
• You are charged for the full stream duration, not just the audio processed.