NexHireG
09/29/2025, 4:38 AMChiranjeet Mishra
09/29/2025, 4:38 AMVapi Support Bot
09/29/2025, 4:39 AMcallerId in your transfer destination, but note that this only works reliably with Twilio. For example:
json
{
"type": "transferCall",
"destinations": [
{
"type": "number",
"number": "+1234567890",
"callerId": "+1987654321"
}
]
}
If you're using SIP or another provider, caller ID may not be passed through due to provider limitations. For SIP, check if your provider supports custom SIP headers for caller ID and configure accordingly.
Sources:
- [Call Forwarding](https://docs.vapi.ai/call-forwarding)
- [Discord: Warm transfers not working](https://discord.com/channels/1211482211119796234/1366650099035541544)NexHireG
09/29/2025, 4:44 AMNexHireG
09/29/2025, 7:51 AMjson{
"type": "transferCall",
"destinations": [
{
"type": "number",
"number": "[operator_number]",
"callerId": "[assistant_phone_number]"
}
]
}
Business Impact
Operators cannot identify calls coming from the assistant system
Call routing and screen pop systems rely on correct caller ID
Affects operational workflow and reporting accuracy
Questions for Vapi Team
Is this a known limitation of the warm-transfer-experimental feature?
Are there specific configuration requirements for caller ID override in warm transfers vs standard transfers?
Is there a difference in how caller ID is handled between the experimental and standard warm transfer implementations?
Can you verify if the issue is reproducible with the provided call ID and tool ID?
Requested Resolution
Fix caller ID passthrough for warm-transfer-experimental feature
Or provide specific configuration guidance to achieve the desired behavior
Clarify if this is a provider-specific limitation that cannot be resolvedNexHireG
09/30/2025, 10:36 AMChiranjeet Mishra
10/01/2025, 6:53 AMNexHireG
10/07/2025, 1:22 AMNexHireG
10/14/2025, 4:36 AMNexHireG
10/14/2025, 4:36 AMNexHireG
10/18/2025, 8:05 AMChiranjeet Mishra
11/03/2025, 9:44 PMNexHireG
11/06/2025, 4:09 PMNexHireG
11/06/2025, 4:09 PM