> ## Documentation Index
> Fetch the complete documentation index at: https://cobo.com/payments/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction to Callbacks

Callbacks are a confirmation mechanism that the Cobo payments service uses to request your approval before executing a sensitive operation. When an operation that requires callback confirmation is triggered, Cobo sends a request to your registered callback endpoint. Your endpoint must respond with an approval or denial before Cobo proceeds.

Callbacks differ from webhooks in an important way:

* **Webhooks** notify your application after an event has occurred.
* **Callbacks** ask your application to approve or deny an operation before it is executed.

Currently, only **Bulk Send** triggers callback confirmation. For each operation in a Bulk Send — whether it uses smart contracts or regular transfers — Cobo calls your callback endpoint so that you can inspect the transaction details and approve or deny before Cobo proceeds.

## Handle callback messages

Follow the steps below to handle callback messages from the Cobo payments service:

1. Create a callback endpoint.
   * Choose a server environment.
   * Define an endpoint URL.
2. Implement the handling logic on the server side.
   * Parse the callback request.
   * Verify the signature.
   * Approve or deny the operation.
3. Register the endpoint on Cobo Portal.

To create an endpoint and implement the handling logic, see [Set up a callback endpoint](/payments/en/developer-tools/set-up-callback-endpoint).

To register the endpoint, see [Set up a callback endpoint](/payments/en/developer-tools/set-up-callback-endpoint#register-the-endpoint).