Unassign Number from Trunk

Remove the link between a phone number and a SIP trunk.

This API endpoint allows you to remove the assignment between a phone number and a SIP trunk. After unassignment, the number will remain in your account inventory but will no longer route calls through the previously assigned trunk.

Warning: Unassigning a number from a trunk will immediately stop routing inbound calls to that number. Ensure you have an alternative routing configuration or reassign the number to a different trunk if you want to continue receiving calls.

HTTP Request

DELETEhttps://api.vobiz.ai/api/v1/account/{ACCOUNT_ID}/numbers/{PHONE_NUMBER}/assign

URL Encoding Notice:

Always encode the phone number in the URL. Use %2B instead of the + symbol. For example:%2B912271264217 (not +912271264217). Failure to encode properly may result in a 404 error.

Authentication Required:

• X-Auth-ID: Your account ID (e.g., MA_BN2MZ1VV)
• X-Auth-Token: Your account Auth Token
• Content-Type: application/json

Note: This endpoint uses the DELETE HTTP method on the same URL path as the assignment endpoint. No request body is required.

URL Parameters

Path Parameters

Name	Type	Description
`ACCOUNT_ID`Required	string	Your unique Vobiz account identifier (e.g., MA_BN2MZ1VV). Must match your X-Auth-ID header.
`PHONE_NUMBER`Required	string	The phone number to unassign, URL-encoded. Use %2B instead of + (e.g., %2B912271264217).

No Request Body Required: The DELETE method does not require a request body. The phone number specified in the URL will be unassigned from its currently associated trunk.

Response

On successful unassignment, the API returns a 204 No Content status with no response body. This indicates the number has been successfully unlinked from the trunk.

Success Response - 204 No Content

HTTP/1.1 204 No Content
Date: Thu, 23 Jan 2026 07:07:24 GMT
Server: Vobiz API Gateway

Error Responses

Error Response - 404 Not Found (Invalid Phone Number)

{
  "error": "Number not found",
  "message": "The phone number could not be found or is not assigned to any trunk."
}

Error Response - 400 Bad Request (Invalid Format)

{
  "error": "invalid request",
  "message": "The phone number format is invalid. Ensure it is URL-encoded correctly."
}

Examples

cURL - Unassign Number from Trunk

cURL Request

curl -X DELETE "https://api.vobiz.ai/api/v1/account/{ACCOUNT_ID}/numbers/%2B1234567890/assign" \
  -H "X-Auth-ID: {ACCOUNT_ID}" \
  -H "X-Auth-Token: {AUTH_TOKEN}" \
  -H "Content-Type: application/json"

Generic Template (Use Your Own Values)

cURL Template

curl -X DELETE "https://api.vobiz.ai/api/v1/account/{ACCOUNT_ID}/numbers/{PHONE_NUMBER}/assign" \
  -H "X-Auth-ID: {ACCOUNT_ID}" \
  -H "X-Auth-Token: {AUTH_TOKEN}" \
  -H "Content-Type: application/json"

Quick Tips:

• Success Code: Look for 204 No Content response
• URL Encoding: Always use %2B instead of + in the phone number
• No Request Body: DELETE requests do not require a request body
• Number Format: Use E.164 format with country code (e.g., +1234567890)

Important Considerations:

• Immediate Effect: Unassignment takes effect immediately; inbound calls will no longer route
• Number Retention: The number remains in your account inventory after unassignment
• Reassignment: You can reassign the number to a different trunk or the same trunk later
• Billing: Number rental charges continue until you release the number using the Unrent Number endpoint

Next Steps:

• Reassign to a different trunk using the Assign Number endpoint
• Or, release the number entirely using the Unrent Number endpoint
• Verify the unassignment by listing your trunk details
• Update your application logic to handle the routing change

Assign Number to Trunk

Delete a Trunk