---
title: "Custom User Validation"
url: https://docs.catalyst.zoho.com/en/sdk/java/v1/cloud-scale/authentication/custom-user-validation/
description: "This page describes the method to add new end-users to your Java application using Catalyst Authentication with sample code snippets."
last_updated: 2025-11-19T15:07:41Z
service: Cloud Scale
type: general
related_links:
  - name: "Authentication"
    url: /en/cloud-scale/help/authentication/introduction
---

# Custom User Validation

Catalyst Authentication allows you to authorize and validate your end-users using a custom [Basic I/O function](https://docs.catalyst.zoho.com/en/serverless/help/functions/basic-io/) on the event of a sign-up to your Catalyst application. You can write your own logic and process the credentials that the user provides through this function, and grant access to your application.

A sample code for a [Custom User Validation](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/whitelisting/custom-user-validation/introduction/) function is given below.

#### Sample Code Snippet

**Package Imports**

```java
import com.catalyst.Context;
import com.catalyst.basic.BasicIO;
import com.catalyst.basic.ZCFunction;
import com.zc.api.APIConstants.ZCSignupValidationStatus;
import com.zc.common.ZCProject;
import com.zc.component.auth.ZCSignupResponseUserDetails;
import com.zc.component.auth.ZCSignupUserValidationRequest;
import com.zc.component.auth.ZCSignupUserValidationResponse;
import com.zc.component.users.ZCSignupUserService;

```

The validation logic can be set based on your preference. In this example, we have depicted the logic with `@notallowedemail`. If the user tries to sign up using a disallowed email addressed, the user will not be allowed to sign up.

```java
public class MainClass implements ZCFunction {
 private static final Logger LOGGER = Logger.getLogger(MainClass.class.getName());
 @Override
    public void runner(Context context, BasicIO basicIO) throws Exception
{
  try 
  {
   ZCProject.initProject();
   ZCSignupUserValidationRequest requestDetails = ZCSignupUserService.getSignupValidationRequest(basicIO);
   if(requestDetails != null) {
    /* Validation logic starts */
    LOGGER.info("Inside null check");
    ZCSignupUserValidationResponse validationResponse = ZCSignupUserValidationResponse.getInstance();
    if(requestDetails.getUserDetails().getEmailId().contains("@notallowedmail")) 
    {
     validationResponse.setStatus(ZCSignupValidationStatus.FAILURE); // The user has failed authentication
    }
    else 
    {
     validationResponse.setStatus(ZCSignupValidationStatus.SUCCESS); // The actions that occur in the event of a successful authentication can be customized
     ZCSignupResponseUserDetails respUserDetails = ZCSignupResponseUserDetails.getInstance();
     respUserDetails.setFirstName("Patricial");
     respUserDetails.setLastName("Boyle");
     respUserDetails.setRoleIdentifier("App User");
     respUserDetails.setOrgId("1241113");
     validationResponse.setUserDetails(respUserDetails);
    }
    basicIO.write(validationResponse);
    /* Validation logic ends */
   }
  }
  catch(Exception e) 
  {
   basicIO.write(e);
   LOGGER.log(Level.SEVERE,"Exception in MainClass",e);
   basicIO.setStatus(500);
  }
 }
}
```

To test this function, you can pass the details of the user in the following `.JSON` format:

```json
{
"request_type": "add_user",
"request_details": 
{
"user_details": 
{
"email_id": "emmy@zylker.com",
"first_name": "Emma",
"last_name": "Thompson",
"org_id": "65**************",
"role_details": 
{
"role_name": "Moderator",
"role_id": "10*****"
}
},
"auth_type": "web"
}
}
```