---
title: "Implementation"
url: https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/whitelisting/custom-user-validation/implementation/
description: "Custom User Validation allows you to validate user sign ups using custom logic"
last_updated: 2026-08-28T06:26:16Z
service: Cloud Scale
type: general
---

# Implementation

To use the *Whitelisting* section you have to configure at least one authentication type: [Hosted Authentication Type](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/native-catalyst-authentication/hosted-authentication-type/introduction/), [Embedded Authentication Type](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/native-catalyst-authentication/embedded-authentication/introduction/), or [Third-party Authentication Type](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/third-party-authentication/introduction/).

You can access the *Whitelisting* by navigating to **Cloud Scale > Authentication** in the console, and clicking the **Whitelisting** option.

![cloud_scale_authentication_whitelisting](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_authentication_whitelisting.webp)

Custom User Validation enables you to validate your end-users using a custom logic as defined by you in a [Basic I/O function](https://docs.catalyst.zoho.com/en/serverless/help/functions/basic-io). 

> **Note:** 

* [Public Signup](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/public-signup)must be enabled to use Custom User Validation

* The custom validation function must already be coded as a Basic I/O, in [Java](https://docs.catalyst.zoho.com/en/sdk/java/v1/cloud-scale/authentication/custom-user-validation/), [Node.js](https://docs.catalyst.zoho.com/en/sdk/nodejs/v2/cloud-scale/authentication/custom-user-validation/), or [Python](https://docs.catalyst.zoho.com/en/sdk/python/v1/cloud-scale/authentication/custom-user-validation/) and present in the Catalyst console in [Serverless Functions](https://docs.catalyst.zoho.com/en/serverless/help/functions/introduction/)

Custom User Validation will be **disabled** by default, and you have the option of configuring it in two ways:

> **Note:**
You can also enable Custom User Validation in the *Additional Settings* section during the last step of all the authentication setups.
![cloud_scale_additional_settings](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_additional_settings.webp)

### Enable Custom User Validation

1. Click the **toggle button** present next to the **Custom User Validation** option in the *Whitelisting* section.
![cloud_scale_authentication_whitelisting](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_authentication_whitelisting.webp)

> **Note:** [Public Signup](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/public-signup/) must be enabled to use Custom User Validation. As mentioned earlier, you can enable while setting up an authentication type using the *Additional Settings* section.

2. Select the [Basic I/O function](https://docs.catalyst.zoho.com/en/serverless/help/functions/basic-io/) that contains your custom logic from the dropdown.
![cloud_scale_custom_validation_funcchoose](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_custom_validation_funcchoose.webp)

3. You can click **JSON Validation** button to view and copy the sample JSON input to test the function. You can test this input with a sample function available in the respective [SDK sections](https://docs.catalyst.zoho.com/en/#DeveloperTools) of each stack, or with your own custom logic.
![cloud_scale_custom_validation_json](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_custom_validation_json.webp)

4. Click **Configure** to finish enabling Custom User Validation.
![cloud_scale_auth_whitelisting_csu_enabled](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_auth_whitelisting_csu_enabled.webp)

### Disable Custom User Validation

You can disable the *Custom User Validation* option if you no longer wish to validate user sign ups using a custom logic, by simply clicking the toggle button to disable *Custom User Validation*.
![cloud_scale_auth_whitelisting_csu_enabled_toggle_highighlit](https://catalyst-docs-development.zohostratus.in/images/help/authentication/cloud_scale_auth_whitelisting_csu_enabled_toggle_highighlit.webp)

Custom User Validation will be disabled, and can be re-enabled again at any time.

> **Note:** Custom User Validation will automatically be disabled for your application if you disable [Public Signup](https://docs.catalyst.zoho.com/en/cloud-scale/help/authentication/public-signup/).