POST

Assign Number to Agent

Assigns an owned phone number to an Agent.

POSThttps://api.vantaxai.com/v1/phone-numbers/{phone_number_id}/assign

Once assigned, inbound calls and messages to the number are handled by the Agent. A number maps to exactly one Agent, and an Agent can hold only one number at a time. The Agent must belong to the same sub-account as the number.

Headers

Authorizationstringrequired
Bearer authentication with your secret API key.
example: Bearer vx_live_3fa9c2…
Content-Typestringrequired
Must be application/json for requests with a body.
example: application/json

Path Parameters

phone_number_idstringrequired
The phone number to assign.
example: pn_55ad12

Body Parameters

agent_idstringrequired
The Agent that will own the number.
example: agt_3d9b21

Request

curl -X POST https://api.vantaxai.com/v1/phone-numbers/pn_55ad12/assign \
  -H "Authorization: Bearer vx_live_3fa9c2..." \
  -H "Content-Type: application/json" \
  -d '{
  "agent_id": "agt_3d9b21"
}'

const res = await fetch(
  "https://api.vantaxai.com/v1/phone-numbers/pn_55ad12/assign",
  {
  method: "POST",
  headers: {
    Authorization: "Bearer vx_live_3fa9c2...",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "agent_id": "agt_3d9b21"
  }),
  }
);
const { data } = await res.json();

import { Vantax } from "@vantax/sdk";

const vantax = new Vantax({ apiKey: process.env.VANTAX_API_KEY! });
// POST /v1/phone-numbers/{phone_number_id}/assign
const result = await vantax.request("POST", "/v1/phone-numbers/{phone_number_id}/assign", {
  "agent_id": "agt_3d9b21"
});

from vantax import Vantax

vantax = Vantax(api_key=os.environ["VANTAX_API_KEY"])
# POST /v1/phone-numbers/{phone_number_id}/assign
result = vantax.request("POST", "/v1/phone-numbers/{phone_number_id}/assign", json={"agent_id": "agt_3d9b21"})

Response

{
  "success": true,
  "message": "Agent assigned successfully",
  "data": {
    "id": "pn_55ad12",
    "number": "+14155550142",
    "country": "US",
    "source": "platform",
    "agent_id": "agt_3d9b21",
    "sub_account_id": "sub_8a1f4c2e",
    "capabilities": {
      "voice": true,
      "sms": true
    },
    "created_at": "2026-01-14T10:30:00Z"
  }
}

{
  "success": false,
  "message": "This Agent is already assigned to another phone number"
}

{
  "success": false,
  "message": "Validation failed",
  "errors": [
    { "field": "agent_id", "message": "agent_id is required" }
  ]
}