This page is a reference for all event types emitted by Conversation Relay and available via the Call Insights Events resource.
All Conversation Relay events include the following base properties:
Property
Type
Description
session_id
string
Session ID of the Conversation Relay session.
sequence_number
integer
Sequence number of the event.
Events with additional payload properties are documented below. Events not listed in the payload sections are timeline markers only and carry no additional properties beyond the base fields.
Speech events
Event
Description
start_of_customer_speech
Customer audio detected — beginning of an utterance.
end_of_customer_speech
Customer stopped speaking; transcription will be sent to your application.
start_of_agent_speech
Virtual agent began playing audio to the customer.
end_of_agent_speech
Virtual agent finished its current response.
Token events
Event
Description
first_token_received
First token received from the application via WebSocket. Marks the end of application latency.
final_token_received
Full text response received from the application.
final_token_received properties
Property
Type
Description
total_tokens
integer
Total number of tokens received.
total_words
integer
Total number of words received.
Latency events
Event
Description
stt_latency
Time from end of customer utterance to full transcription ready.
tts_latency
Time from receiving a text sentence to start of audio synthesis.
Both latency events share the same payload:
Property
Type
Description
latency_ms
integer
Latency in milliseconds.
Interaction events
Event
Description
prompt_sent
Transcription sent to your WebSocket server.
interrupt
One party began speaking while the other was active.
preempted
New agent response tokens arrived, interrupting current agent speech playback.
dtmf
Customer pressed a key on their phone's keypad.
digit
Application sent digits to navigate an IVR.
interrupt properties
Property
Type
Description
type
string
Type of interruption. One of DTMF or SPEECH.
Session events
Event
Description
configurations
Session configuration active at the start of the session.
language_changed
Active language configuration changed during the session.
call_wrap_up
Session has ended and the summary is being finalized.
configurations properties
Property
Type
Description
configurations
object
Key-value pairs of active configuration settings.
languages
object
Key-value pairs of language configurations, each containing tts_provider, voice, transcription_provider, and speech_model.
language_changed properties
Property
Type
Description
tts_language_code
string
Language code for text-to-speech.
transcription_language_code
string
Language code for speech-to-text.
call_wrap_up properties
Property
Type
Description
duration_in_seconds
integer
Session duration in seconds.
end_status
string
Final state of the session. One of unknown, failure, ended, or hung_up.
Media events
Event
Description
play_media
Application requested an audio file to be played instead of synthesized speech.