VAPI•5mo ago

SIP Headers and Workflows

Hello guys, do we know if workflows support SIP headers
?
Because it seems that only the assistant is able to fill the dynamic variables based on the SIP headers
And the workflows do not

76e0f5fb-8340-43d3-9557-74e8c9819b01

VapiAPP•7/24/25, 7:09 PM

Workflows do not natively support SIP headers for dynamic variables only Assistants can auto-fill them via assistantOverrides.variableValuesassistantOverrides.variableValues, so to use SIP headers in a Workflow, you must route the call through an Assistant webhook that injects the variables.. https://docs.vapi.ai/advanced/sip https://docs.vapi.ai/workflows/overview

then-purpleOP•7/24/25, 8:18 PM

Ok thank you very much, let me see if we can integrate this in our work flow

then-purpleOP•7/24/25, 8:18 PM

When doing the SIP integration however

then-purpleOP•7/24/25, 8:18 PM

Given this PCAP

then-purpleOP•7/24/25, 8:18 PM

I see the following

then-purpleOP•7/24/25, 8:19 PM

INVITE sip:prod-vici-auto-screener-sip@sip.vapi.ai SIP/2.0
Via: SIP/2.0/UDP 207.188.10.143:5060;branch=z9hG4bK7d60ec91;rport
Max-Forwards: 70
From: "8169335555" <sip:sip-ai-screener%40datametrix.us@sip.vapi.ai>;tag=as7fe91873
To: <sip:prod-vici-auto-screener-sip@sip.vapi.ai>
Contact: <sip:sip-ai-screener%40datametrix.us@207.188.10.143:5060>
Call-ID: 155fe60759e312f760012948388e5cf0@sip.vapi.ai
CSeq: 102 INVITE
User-Agent: Asterisk PBX 18.26.2-vici
Date: Thu, 24 Jul 2025 16:57:30 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
X-Lead-ID: 96458322
X-Lead-Type: AUTO
X-Model: Toyota
X-Make: Corolla
X-Year: 2021
P-Asserted-Identity: "8169335555" <sip:3055390932@sip.vapi.ai>
Content-Type: application/sdp
Content-Length: 261

then-purpleOP•7/24/25, 8:19 PM

The phone number does NOT appear as 8169337264 it appear as

then-purpleOP•7/24/25, 8:19 PM

And the variable customer.phone NOT being set

Tthen-purple Hello guys, do we know if workflows support SIP headers ? Because it seems that ...

then-purpleOP•7/26/25, 12:24 AM

@Shubham Bajaj call id

VapiAPP•7/31/25, 7:35 AM

Vapi workflows don’t auto-populate customer.phone from SIP INVITE headers, only Assistants do via assistantOverrides, so to set the caller’s number like From: or X-Lead-* headers, you’ll have to handle it in an Assistant webhook and pass it manually as a variable..

then-purpleOP•8/11/25, 1:21 PM

Thanks

then-purpleOP•8/11/25, 1:21 PM

Can you further elaborate?

Ccomprehensive-tomato Vapi workflows don’t auto-populate [customer.phone](http://customer.phone) from ...

then-purpleOP•8/11/25, 1:21 PM

? TY

VapiAPP•8/22/25, 5:15 AM

Hello,

Thanks for patiently waiting.

Vapi workflows currently don’t auto-populate the customer.phonecustomer.phone field from the SIP INVITE headers. This behavior is only available when using Assistants, since they can parse those headers through

assistantOverrides

assistantOverrides

.

If you need to capture the caller’s number (for example, from the From:From: header or custom headers like X-Lead-*X-Lead-*), the way to handle this is through an Assistant webhook. In the webhook, you can extract the caller information from the SIP INVITE headers and then pass it manually into your workflow as a variable.

In other words:

**Workflows** = no automatic mapping from SIP headers → `customer.phone`.
**Assistants** = can override and pull that info with `assistantOverrides`.
**Solution** = use a webhook to grab the header data yourself and inject it into the workflow.Let us know if you need further assistance.

urgent-maroon•10/28/25, 12:34 PM

Hello, can you help me and explain how to create a webhook to grab the header data yourself and inject it into the workflow?

VapiAPP•11/18/25, 4:29 AM

I sincerely apologize for the delayed response to your support request.
We implemented better tracking for support tickets to ensure timely responses going forward, but due to a technical limitation, this only applies to tickets created after this past week.
I'm closing this older ticket, but if your issue still needs attention, please:
Reply with 'REOPEN' or
Email support@vapi.ai with any updates
I'll personally ensure your new request gets prompt attention.
Thank you for your patience.
Best regards,
Vapi Support Team

SIP Headers and Workflows

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