---
title: "Make a call"
method: POST
path: "/calls"
---

# Make a call

`POST /calls`

Initiates a real-time phone call through the AI agent.

## Headers

- `Authorization` string, required

## Request body

- object
  - `model_id` string, required — Agent ID. You can find it on the agent’s page in your dashboard.
  - `phone` string, required — Call recipient's phone number.
  - `from_phone_number` string — Optional outbound caller ID. Must match a phone number attached to the outbound agent.
  - `name` string, required — Call recipient's name.
  - `custom_variables` CallsPostRequestBodyContentApplicationJsonSchemaCustomVariablesItems[] — Key-value pairs of pre-call variables, called custom variables in the API, that you can dynamically inject into the prompt. [Learn more](/variables#pre-call-variables).
    - `key` string
    - `value` string
  - `lead_email` string — The customer's email that can be used to book an appointment.
  - `lead_timezone` string — The customer's time zone that can be used to book an appointment. For a list of all available time zones, see [Time zones](/time-zones).
  - `prompt` string — The prompt that the agent will use.
  - `greeting` string — The greeting the agent will use.

## Response `200`

200

- VoiceCallResponse200
  - `status` string
  - `response` CallsPostResponsesContentApplicationJsonSchemaResponse
    - `answer` string
    - `call_id` string
  - `eta` integer — How long it will take to initialize the call, in seconds.

## Other responses

- `400` — 400

## Changes

- **2026-08-22** `292b6010eb31` — 1 info
  - api tag `` removed

[Change history](https://skmtc.dev/synthflow/apis/platform-api/changes/calls/post.md)

---

[API](https://skmtc.dev/synthflow/apis/platform-api.md) · [All operations](https://skmtc.dev/synthflow/apis/platform-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/synthflow/platform-api/revisions/6976456ad422/schema)