How to pass input variables to Vapi's Workflow, for example: user first_name?

inadequate-blush · 2025-06-06T19:56:34.468Z

I want to make outbound call and if agent have some information about user than that would be great.

V

To pass input variables like

first_name

first_name

first_name

first_name to a Vapi Workflow for outbound calls, include them in the

customer

customer

object when creating the call:

{
  "phoneNumberId": "YOUR_PHONE_NUMBER_ID",
  "assistantId": "YOUR_ASSISTANT_ID",
  "customer": {
    "first_name": "John"
  }
}

{
  "phoneNumberId": "YOUR_PHONE_NUMBER_ID",
  "assistantId": "YOUR_ASSISTANT_ID",
  "customer": {
    "first_name": "John"
  }
}

{
  "phoneNumberId": "YOUR_PHONE_NUMBER_ID",
  "assistantId": "YOUR_ASSISTANT_ID",
  "customer": {
    "first_name": "John"
  }
}

{
  "phoneNumberId": "YOUR_PHONE_NUMBER_ID",
  "assistantId": "YOUR_ASSISTANT_ID",
  "customer": {
    "first_name": "John"
  }
}

In your workflow prompts, use

{{first_name}}

{{first_name}}

{{first_name}}

{{first_name}} to reference this variable and personalize the conversation.
Tip: Make sure your workflow nodes use the exact variable name in the

{{variable_name}}

{{variable_name}}

{{variable_name}}

{{variable_name}} format for dynamic insertion.
See more in the docs

Sources:

⤵️ Mention @Vapi Support Bot for follow-ups 🐥

I

inadequate-blushOP•6/6/25, 8:00 PM

@Duckie I'm using websocket connection with Vapi's workflow

V

Vapi Support BotAPP•6/6/25, 8:02 PM

To pass input variables like

first_name

first_name

first_name

first_name to a Vapi Workflow over websocket, use the

assistantOverrides

assistantOverrides

parameter with

variableValues

variableValues

variableValues

variableValues in your

.start()

.start()

.start()

.start() call:

const assistantOverrides = {
  variableValues: { first_name: "John" }
};
vapi.start("YOUR_WORKFLOW_ID", assistantOverrides);

const assistantOverrides = {
  variableValues: { first_name: "John" }
};
vapi.start("YOUR_WORKFLOW_ID", assistantOverrides);

const assistantOverrides = {
  variableValues: { first_name: "John" }
};
vapi.start("YOUR_WORKFLOW_ID", assistantOverrides);

const assistantOverrides = {
  variableValues: { first_name: "John" }
};
vapi.start("YOUR_WORKFLOW_ID", assistantOverrides);

In your workflow, reference

{{first_name}}

{{first_name}}

{{first_name}}

{{first_name}} to personalize the conversation.
Tip: Make sure your workflow nodes use the exact variable name in the

{{variable_name}}

{{variable_name}}

{{variable_name}}

{{variable_name}} format for dynamic insertion.
See Web SDK docs for more details.

Sources:

E

extreme-purple•6/7/25, 7:38 AM

Integrate your CRM to fetch data, personalize assistant prompts with that info, automate call triggers via tools like Make.com, and ensure real-time data is available during the call..

I

inadequate-blushOP•6/7/25, 9:09 AM

One more -- there is such a high latency in Workflow than Assistant. Is there any way we can reduce them ? (I'm building voice agent for hindi support)

E

extreme-purple•6/7/25, 9:13 AM

Use streaming STT/TTS, semantic VAD, faster or smaller LLMs like GPT-4o mini, cached responses, and host services regionally, while avoiding HTTP-based delays by switching to WebSockets where possible..

How to pass input variables to Vapi's Workflow, for example: user first_name?

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