---
title: "Check SSO user login ID"
slug: "validate-user-login-id"
updated: 2026-09-17T10:05:35Z
published: 2026-09-17T10:05:35Z
canonical: "api.ncloud-docs.com/validate-user-login-id"
---

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

# Check SSO user login ID

Available in Classic and VPC

Check the validity and duplication of an SSO user login ID.

## Request

This section describes the request format. The method and URI are as follows:

| Method | URI |
| --- | --- |
| GET | /api/v1/users/check-login-id |

### Request headers

For information about the headers common to all Ncloud Single Sign-On APIs, see [Ncloud Single Sign-On request headers](/docs/en/single-sign-on-overview#%EC%9A%94%EC%B2%AD%ED%97%A4%EB%8D%94).

### Request query parameters

You can use the following query parameters with your request:

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `loginId` | String | Optional | SSO user login ID - 3-60 characters - Email format - URL encoding required |

### Request example

The request example is as follows:

```
curl --location --request GET 'https://sso.apigw.ntruss.com/api/v1/users/check-login-id?loginId=******%40ncloud.com' \
--header 'x-ncp-apigw-timestamp: {Timestamp}' \
--header 'x-ncp-iam-access-key: {Access Key}' \
--header 'x-ncp-apigw-signature-v2: {API Gateway Signature}'
```

## Response

This section describes the response format.

### Response body

The response body includes the following data:

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `name` | String | - | SSO user login ID |
| `success` | Boolean | - | API processing result |

### Response status codes

For information about the response status codes common to all Ncloud Single Sign-On APIs, see [Ncloud Single Sign-On response status codes](/docs/en/single-sign-on-overview#%EC%9D%91%EB%8B%B5%EC%83%81%ED%83%9C%EC%BD%94%EB%93%9C).

### Response example

The response example is as follows:

#### If the check shows that the ID is available

The following is a sample response if the check result is an available ID.

```
{
    "name": "******@ncloud.com",
    "success": true
}
```

#### If the check shows that the ID is unavailable

The following is a sample response if the check result is an unavailable ID.

- If the login ID is already in use

```
{
    "name": "******@ncloud.com",
    "success": false,
    "message": "Duplicate login ID."
}
```
- If the login ID is invalid

```
{
    "name": "userid",
    "success": false,
    "message": "Invalid login ID."
}
```