dynamic transfer call webhook not wokring

popular-magenta · 2025-08-11T13:25:35.798Z

I setted up the dynamic transfer tool and bind it with the assistant, but the webhook logs and my server not recieved any transfer call request.

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popular-magentaOP•8/11/25, 1:26 PM

Call ID: bd36bcc4-af42-4728-9e9e-b8b93f43176b

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spotty-amber•8/11/25, 1:49 PM

Same or similar issue here. VAPI stopped sending transfer-destination-request seemingly out of nowhere at around 3:30pm EST Friday.

Sspotty-amber Same or similar issue here. VAPI stopped sending transfer-destination-request se...

B

brilliant-orange•8/12/25, 2:25 PM

I am having the same issue as well! Seems like a bug. Can someone please help!

K

KyleAPP•8/13/25, 7:10 AM

The main issue is that you have "destinations": [] in your transfer tool configuration. For dynamic transfers with transfer-destination-request, you need to either:

Remove the destinations property entirely (recommended)
Don't provide an empty array - this tells Vapi that destinations are pre-defined

Once you remove the destinations property, the AI will call your dynamicTransfer function, and Vapi will send a transfer-destination-request webhook to your server URL for you to validate and provide the final destination.

Try updating your transfer tool configuration by removing the "destinations": [] line and you should start receiving the webhook events!

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popular-magentaOP•8/13/25, 8:59 AM

Looks like it's not correct in hte official document

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popular-magentaOP•8/13/25, 9:00 AM

@Vapi Maybe you guys should fix the document pls

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popular-magentaOP•8/13/25, 9:07 AM

It won't do dynamic transfer even if I remove the destination arrayy

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popular-magentaOP•8/13/25, 9:08 AM

call id: d42da8fe-a727-4b26-bfc7-8c05946f8ba9

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popular-magentaOP•8/13/25, 9:09 AM

I also observe a intersting thing is the forwarding number is using the "content" as the number

K

KyleAPP•8/14/25, 6:01 AM

You can try these two configurations to see if they work for you:

option 1:

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

option 2:

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

{
  "parameters": {
    "type": "object",
    "properties": {
      "destination": {
        "type": "string",
        "description": "The number to transfer the call to. In the format of E.164 default country code is +1"
      }
    },
    "required": ["destination"]
  }
}

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popular-magentaOP•8/14/25, 8:29 AM

but I also want LLM to generate the content, how can I set the content that I want LLM to say?

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popular-magentaOP•8/14/25, 8:30 AM

This is my webhook logic

                console.error(
                    "[ZONIC-VAPI-WEBHOOK] No transfer number provided in function call parameters",
                );
                throw new Error("Transfer number is required");
            }

            console.log(`[ZONIC-VAPI-WEBHOOK] Transferring to: ${number} with message: "${content}"`);

            // Return the transfer destination response
            const response: VapiTransferDestinationResponse = {
                destination: {
                    type: "number",
                    number: number,
                    message: {
                        type: "request-start",
                        content: content,
                    },
                },
            };

                console.error(
                    "[ZONIC-VAPI-WEBHOOK] No transfer number provided in function call parameters",
                );
                throw new Error("Transfer number is required");
            }

            console.log(`[ZONIC-VAPI-WEBHOOK] Transferring to: ${number} with message: "${content}"`);

            // Return the transfer destination response
            const response: VapiTransferDestinationResponse = {
                destination: {
                    type: "number",
                    number: number,
                    message: {
                        type: "request-start",
                        content: content,
                    },
                },
            };

                console.error(
                    "[ZONIC-VAPI-WEBHOOK] No transfer number provided in function call parameters",
                );
                throw new Error("Transfer number is required");
            }

            console.log(`[ZONIC-VAPI-WEBHOOK] Transferring to: ${number} with message: "${content}"`);

            // Return the transfer destination response
            const response: VapiTransferDestinationResponse = {
                destination: {
                    type: "number",
                    number: number,
                    message: {
                        type: "request-start",
                        content: content,
                    },
                },
            };

                console.error(
                    "[ZONIC-VAPI-WEBHOOK] No transfer number provided in function call parameters",
                );
                throw new Error("Transfer number is required");
            }

            console.log(`[ZONIC-VAPI-WEBHOOK] Transferring to: ${number} with message: "${content}"`);

            // Return the transfer destination response
            const response: VapiTransferDestinationResponse = {
                destination: {
                    type: "number",
                    number: number,
                    message: {
                        type: "request-start",
                        content: content,
                    },
                },
            };

Ccomprehensive-tomato You can try these two configurations to see if they work for you: option 1: ``...

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popular-magentaOP•8/14/25, 10:47 AM

that is exactly same from option 1 and option 2

Ccomprehensive-tomato You can try these two configurations to see if they work for you: option 1: ``...

P

popular-magentaOP•8/15/25, 8:40 AM

Tested still not working...

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popular-magentaOP•8/15/25, 8:41 AM

It still not sending the transfer-destination-request to my webhook

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popular-magentaOP•8/15/25, 8:42 AM

However, it shows in call logs that it use DynamicTrnsfer for forwarding the phone call

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popular-magentaOP•8/15/25, 8:43 AM

but nothing has sent to webhook, even in webhook logs doesn't show it

K

KyleAPP•8/18/25, 5:13 PM

Could you please share the call id for the call made from the screenshot you sent?

P

popular-magenta•8/26/25, 1:23 AM

Any update on this? I followed the same tutorial and am not seeing any webhooks coming through. With or without the destinations array

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popular-magenta•8/26/25, 1:30 AM

I found a

handoff-destination-request

handoff-destination-request

handoff-destination-request

handoff-destination-request with the handoff tool in the API, but it just hangs and never does a hdnoff, though I am not sure what the response should be from the webhook because it is not documented anywhere

K

KyleAPP•8/27/25, 11:23 PM

Hey Noah, the handoff tool is for assistant-to-assistant transfers, so if you are trying to transfer to an external destination we recommend sticking with the regular transferCall tool. Here are some guidelines for ensuring the transfer-destination-request webhook gets sent:

Enable the server event in your assistant configuration
Configure a dynamic transfer tool without pre-defined destinations
Set up a proper webhook endpoint that returns the destination
Ensure your webhook URL is accessible and responds quickly

If you're still not receiving webhooks after following these steps, check your assistant configuration in the Vapi dashboard to verify that both the serverEvents and serverUrl are properly set.

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popular-magenta•8/28/25, 3:17 PM

That makes sense. We did get assistant-to-assistant transfers working

K

KyleAPP•9/1/25, 9:56 AM

Glad you were able to get this resolved. If anything else comes up or you need further assistance, we’re here to help.

Ccomprehensive-tomato Could you please share the call id for the call made from the screenshot you sen...

E

endless-jade•9/15/25, 8:03 PM

Facing the exact same issue here even after removing the

destination

destination

destination

destination entirely, I can't get VAPI to fire the

transfer-destination-request

transfer-destination-request

transfer-destination-request

transfer-destination-request event - I've opened a ticket with my test Call IDs here supportDynamic transfer not working: `transfer-destination-request` not being fired

K

KyleAPP•9/17/25, 7:25 PM

Thanks for flagging it. We will respond to that ticket instead and close this one out.

dynamic transfer call webhook not wokring

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