Hey @Rajkamal Singh Jhala,

Since you have already consumed a Register API and saved data locally, for status update via callback you need to expose a REST API.

Step-by-Step Approach:

1.Expose REST API
Go to Logic → Integrations → Expose → REST API
Create a new REST API (e.g. Callback_Status_API)

2.Define Callback Method
Add a POST method (recommended)
Example endpoint:- /updateStatus

3.Define Input Parameters
Match what Producer will send, for example:
 Aadhar,Pan

4.Implement Server Action Logic
In the method flow:
 Fetch record from local table using Aadhar / Pan / ReferenceId
 Update Status field
 Save changes
Handle “record not found” scenario properly

5.Return Proper Response
Example response:
{
  "success": true,

  "message": "Status updated successfully"
}

Hope it help you.

Thanks & Regards,
Kundan Chauhan

In OutSystems, a callback API is implemented by exposing a REST endpoint that the external producer can call to notify a status update. There is no special “callback” construct beyond this pattern.

Given your scenario, the usual and correct approach is:

• Expose a REST API in Logic → Integrations → Expose → REST

• Define a POST method that receives a status update payload from the producer

• Use a technical correlation identifier (for example, a reference ID returned during the initial Register API call) to locate the record stored locally

• Update only the relevant status fields and persist the changes

• Return an appropriate HTTP response indicating the outcome (e.g. success, record not found, validation error)

From a design and security perspective:

• Avoid using sensitive personal identifiers (Aadhaar, PAN, etc.) as the primary lookup key for callbacks

• Keep the callback logic minimal and independent from UI flows

• Secure the exposed REST API using the authentication mechanism agreed with the producer

This pattern is the standard way to handle asynchronous status updates from external systems in OutSystems.