Hello, I defined "Transfer Call" as Tools. I also give SIP type sipUri as Definitions. As soon as the forwarding is done to the other party, the call is immediately terminated with BYE message. When I talked to the forwarded provider, they said that if you forward the call you sent to us with Invite message instead of Refer parameter, it will be activated successfully. In the documentation (https://docs.vapi.ai/api-reference/tools/create#request.body.transferCall.destinations.sip.transferPlan.sipVerb) I saw "bye" and "dial" instead of "sipVerb": "refer". How can I forward as INVITE? Thanks.

Hi there! 👋 I understand you're having an issue with call forwarding where calls are being terminated immediately after forwarding with a BYE message. Your provider suggested using INVITE instead of REFER, and you're looking for how to configure this in Vapi. I can definitely help with configuring call forwarding to use the INVITE method instead of REFER with your SIP trunk! According to the information I found, you can configure the Transfer Call tool to use SIP INVITE by setting the

sipVerb

parameter to

"invite"

within the

transferPlan

for your SIP destination. Here's how to do it:

json
{
  "destinations": [
    {
      "type": "sip",
      "sipUri": "sip:your-sip-uri-here",
      "transferPlan": {
        "mode": "blind-transfer",
        "sipVerb": "invite"
      }
    }
  ]
}

This configuration will cause Vapi to use SIP INVITE when transferring the call to your specified SIP URI instead of using the default REFER method [source](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1337383511329345588). When implementing this, make sure to: 1. Keep your existing SIP URI configuration 2. Add the

transferPlan

object if you don't already have it 3. Set the

mode

to "blind-transfer" (or another appropriate mode for your use case) 4. Add the

sipVerb

parameter with the value

"invite"

Is there anything else you'd like to know about configuring call forwarding with the INVITE method? Source: - [Discord thread about using SIP INVITE with Transfer Call tool](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1337383511329345588)

To forward calls using the INVITE method, set "sipVerb": "dial" in your transfer plan’s SIP configuration..

Thanks for the feedback. There is no field to enter sipVerb value in the UI under Tools in the Dashboard. Under API Reference, "sipVerb": {} in key-value dict format. Only string value entry as "sipVerb": "dial" is not available in the API Reference UI. However, we can assign by sending POST data ourselves. https://docs.vapi.ai/api-reference/tools/create/~explorer I will try and give feedback.

Follow this https://cdn.discordapp.com/attachments/1361215907006775398/1361831514471530526/image.png?ex=68002fee&is=67fede6e&hm=47ed686cf6197d71bdf3adf9435da8306f80ee4666ddca5f3b7d71411a22b087&