The List scheduled callbacks endpoint returns scheduled callback tasks created in your contact center.

Requirements: Base URL, Authentication, Error codes

Scope: tasks.scheduled_callbacks.manage

What this does

When you send a List scheduled callbacks request,

When to use it

• Show upcoming callbacks in a CRM or admin tool
• Sync callback tasks into an external system
• Retrieve callback IDs to use with Get scheduled callback

Prerequisites

• Scheduled callbacks must be enabled for your contact center.

Endpoint

GET /api/v4/tasks/scheduled_callbacks

Query parameters

All query parameters are optional.

• limit
  The number of items to return. Default is 100. Maximum is 100.
• offset
  The number of items to skip before collecting results. Default is 0.

Examples

Minimal request

curl -X GET "https://{cluster_id}.voiso.com/api/v4/tasks/scheduled_callbacks" \
  -H "Authorization: Bearer <contact_center_api_key>" \
  -H "Content-Type: application/json"

Request the third page of results (20 per page)

curl -X GET "https://{cluster_id}.voiso.com/api/v4/tasks/scheduled_callbacks?limit=20&offset=40" \
  -H "Authorization: Bearer <contact_center_api_key>" \
  -H "Content-Type: application/json"

Response

If successful, the API returns an array of scheduled callback objects and pagination metadata.

{
  "scheduled_callbacks": [
    {
      "id": 149,
      "phone_number": "18885658889",
      "scheduled_at": "2025-12-12T12:00:00.000+02:00",
      "user": {
        "id": "1234",
        "name": "Jane Doe",
        "email": "[email protected]"
      },
      "caller_id_group": {
        "id": 1,
        "name": "Default"
      },
      "note": "Follow up call",
      "related_call": null,
      "source": {
        "system": "zoho",
        "account_id": "ACC01"
      },
      "status": "pending"
    }
  ],
  "metadata": {
    "total": 100
  }
}

Notes

• scheduled_at is returned in ISO 8601 format.
• note, related_call, and source can be null if they were not provided when the callback was created.

Troubleshooting

401 Unauthorized

What to check:

• You are sending Authorization: Bearer <contact_center_api_key>.
• Your Base URL includes the correct {cluster_id}.

403 Forbidden

Common causes:

• Scheduled callbacks are not enabled for the contact center.
• Your API key does not have access to scheduled callback resources.

429 Too many requests

What to do:

• Reduce request frequency and retry with backoff.