---
title: "Check email uniqueness"
type: reference
method: GET
path: /rest-api/user-preference/check-email.do
tag: "Users"
---

# Check email uniqueness

`GET https://YOUR-NETWORK-DOMAIN/rest-api/user-preference/check-email.do`

Checks whether the given email address is already registered in the system. Returns a JSON response with an 'exist' boolean field: true if the email is taken, false if available. Useful for client-side form validation when creating a user, to give immediate feedback before submitting the full form. Only a role that may create users can call it, so other accounts cannot probe which addresses are registered.

## Query params

| Name | Type | Required | Example | Description |
|---|---|---|---|---|
| `email` | string | yes | `user@example.com` | The email address to check for uniqueness. URL-encoded if it contains special characters. |

## Responses

- `200` — Email check result. Response: {success: true, exist: true/false}
- `400` — Not an e-mail address
- `401` — Unauthorized — authentication error
- `403` — The caller's role may not create users

## Example request

```bash
curl --request GET \
  --url 'https://YOUR-NETWORK-DOMAIN/rest-api/user-preference/check-email.do?email=user%40example.com' \
  --header 'X-Api-Key: YOUR_API_KEY'
```

Source: https://epom.com/ad-server/docs/api/users/get-user-preference-check-email