> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.onesignal.com/llms.txt
> Use this file to discover all available pages before exploring further.
# View user identity
> Retrieve all aliases associated with a user using a known alias, such as an `external_id`, `onesignal_id`, or a custom alias. This API helps you map back to a user’s full identity from any one piece of identifying information.
## Overview
Use this API when you want to retrieve the complete identity object for a user, which includes all aliases tied to that user. It is ideal for cases where you know one alias and want to discover others—especially helpful for user mapping, debugging, or linking systems.
This endpoint is similar to the [View user](/reference/view-user) API but only returns the `identity` object—not subscriptions or properties.
If you only know a subscription\_id, use View user identity (by subscription) instead.
For more context on user identity and aliasing:
* [Users](/docs/en/users)
* [Aliases](/docs/en/aliases)
***
## How to use this API
To identify the user, use:
* `alias_label` – the type of alias you’re using to find the user (e.g. `external_id`, `onesignal_id`, or a custom alias)
* `alias_id` – the actual value of that alias
Common usage patterns:
Using `external_id` (recommended):
* `alias_label`: `external_id`
* `alias_id`: your user ID (e.g., user-123)
Using `onesignal_id`:
* `alias_label`: `onesignal_id`
* `alias_id`: the OneSignal-assigned unique ID
Using a custom alias:
* Define your own alias label (e.g. `shopify_customer_id`) and its value
We strongly recommend setting and using the `external_id` as your primary user identifier for portability and simplicity across your systems.
***
## OpenAPI
````yaml GET /apps/{app_id}/users/by/{alias_label}/{alias_id}/identity
openapi: 3.1.0
info:
title: api.onesignal.com
version: '11.6'
servers:
- url: https://api.onesignal.com
security:
- {}
paths:
/apps/{app_id}/users/by/{alias_label}/{alias_id}/identity:
get:
summary: View user identity
description: >-
Retrieve all aliases associated with a user using a known alias, such as
an `external_id`, `onesignal_id`, or a custom alias. This API helps you
map back to a user’s full identity from any one piece of identifying
information.
operationId: fetch-aliases
parameters:
- name: app_id
in: path
description: >-
Your OneSignal App ID in UUID v4 format. See [Keys &
IDs](/docs/en/keys-and-ids).
schema:
type: string
required: true
- name: alias_label
in: path
description: >-
The alias name or key to locate the user. Most commonly set as
`external_id` but can be the `onesignal_id` or a [custom
alias](/docs/aliases).
schema:
type: string
required: true
- name: alias_id
in: path
description: The specific identifier for the given alias to identify the user.
schema:
type: string
required: true
- name: Authorization
in: header
description: >-
Your App API key with prefix `Key `. See [Keys &
IDs](/docs/en/keys-and-ids).
required: true
schema:
type: string
default: Key YOUR_APP_API_KEY
responses:
'200':
description: '200'
content:
application/json:
schema:
type: object
properties:
identity:
type: object
properties:
onesignal_id:
type: string
description: >-
The OneSignal ID of the user. See
[Users](/docs/users).
example: OneSignal-ID-in-UUID-v4-format
external_id:
type: string
description: The External ID of the user. See [Users](/docs/users).
example: the-users-external-id
'400':
description: '400'
content:
application/json:
schema:
$ref: '#/components/schemas/StructuredErrorResponse'
example:
errors:
- code: internal error code
title: example error title
'404':
description: '404'
content:
application/json:
schema:
$ref: '#/components/schemas/StructuredErrorResponse'
example:
errors:
- code: internal error code
title: example error title
'429':
description: >-
Rate limit exceeded. Wait the number of seconds in the `Retry-After`
header before retrying.
headers:
Retry-After:
description: >-
Number of seconds to wait before retrying the request. Always
emitted on 429 responses.
schema:
type: integer
minimum: 0
content:
application/json:
schema:
$ref: '#/components/schemas/StructuredErrorResponse'
example:
errors:
- code: Rate Limit Exceeded
title: API rate limit exceeded
'503':
description: >-
Service temporarily unavailable. Retry after a short backoff. The
body may be empty or non-JSON in some failure modes.
headers:
Retry-After:
description: >-
Number of seconds to wait before retrying. Optional — may be
absent when the response is generated upstream.
schema:
type: integer
minimum: 0
content:
application/json:
schema:
$ref: '#/components/schemas/BasicErrorResponse'
example:
errors:
- Service temporarily unavailable
deprecated: false
x-codeSamples:
- lang: typescript
label: Node.js SDK
source: |-
import Onesignal from '@onesignal/node-onesignal';
const configuration = Onesignal.createConfiguration({
restApiKey: '',
});
const apiInstance = new Onesignal.DefaultApi(configuration);
// string
const appId: string = "00000000-0000-0000-0000-000000000000";
// string
const aliasLabel: string = "external_id";
// string
const aliasId: string = "YOUR_USER_EXTERNAL_ID";
try {
const response = await apiInstance.getAliases(appId, aliasLabel, aliasId);
console.log(response);
} catch (e) {
if (e instanceof Onesignal.ApiException) {
// `e.errorMessages` flattens any error-envelope shape to a `string[]`;
// the raw parsed body remains on `e.body`.
console.error("getAliases failed: HTTP " + e.code, e.errorMessages);
} else {
throw e;
}
}
- lang: python
label: Python SDK
source: >-
import onesignal
from onesignal.api import default_api
from onesignal.models import *
from pprint import pprint
# See configuration.py for a list of all supported configuration
parameters.
# Some of the OneSignal endpoints require ORGANIZATION_API_KEY token
for authorization, while others require REST_API_KEY.
# We recommend adding both of them in the configuration page so that
you will not need to figure it out yourself.
configuration = onesignal.Configuration(
rest_api_key = "YOUR_REST_API_KEY", # App REST API key required for most endpoints
organization_api_key = "YOUR_ORGANIZATION_KEY" # Organization key is only required for creating new apps and other top-level endpoints
)
# Enter a context with an instance of the API client
with onesignal.ApiClient(configuration) as api_client:
# Create an instance of the API class
api_instance = default_api.DefaultApi(api_client)
app_id = "00000000-0000-0000-0000-000000000000"
alias_label = "external_id"
alias_id = "YOUR_USER_EXTERNAL_ID"
# example passing only required values which don't have defaults set
try:
api_response = api_instance.get_aliases(app_id, alias_label, alias_id)
pprint(api_response)
except onesignal.ApiException as e:
print("Exception when calling DefaultApi->get_aliases: %s\n" % e)
print("Status Code: %s" % e.status)
print("Response Body: %s" % e.body)
- lang: php
label: PHP SDK
source: |-
setRestApiKeyToken('YOUR_REST_API_KEY')
->setOrganizationApiKeyToken('YOUR_ORGANIZATION_API_KEY');
$apiInstance = new onesignal\client\Api\DefaultApi(
// If you want use custom http client, pass your client which implements `GuzzleHttp\ClientInterface`.
// This is optional, `GuzzleHttp\Client` will be used as default.
new GuzzleHttp\Client(),
$config
);
$app_id = '00000000-0000-0000-0000-000000000000'; // string
$alias_label = 'external_id'; // string
$alias_id = 'YOUR_USER_EXTERNAL_ID'; // string
try {
$result = $apiInstance->getAliases($app_id, $alias_label, $alias_id);
print_r($result);
} catch (\onesignal\client\ApiException $e) {
echo 'Exception when calling DefaultApi->getAliases: ', $e->getMessage(), PHP_EOL;
echo 'Status Code: ', $e->getCode(), PHP_EOL;
// getErrorMessages() flattens any error-envelope shape to a string[];
// the raw body remains on getResponseBody().
echo 'Error Messages: ', implode(', ', $e->getErrorMessages()), PHP_EOL;
echo 'Response Body: ', $e->getResponseBody(), PHP_EOL;
} catch (\Exception $e) {
echo 'Exception when calling DefaultApi->getAliases: ', $e->getMessage(), PHP_EOL;
}
- lang: go
label: Go SDK
source: |-
package main
import (
"context"
"fmt"
"os"
"github.com/OneSignal/onesignal-go-api/v5"
)
func main() {
appId := "00000000-0000-0000-0000-000000000000" // string |
aliasLabel := "external_id" // string |
aliasId := "YOUR_USER_EXTERNAL_ID" // string |
configuration := onesignal.NewConfiguration()
apiClient := onesignal.NewAPIClient(configuration)
restAuth := context.WithValue(context.Background(), onesignal.RestApiKey, "YOUR_REST_API_KEY") // App REST API key required for most endpoints
resp, r, err := apiClient.DefaultApi.GetAliases(restAuth, appId, aliasLabel, aliasId).Execute()
if err != nil {
fmt.Fprintf(os.Stderr, "Error when calling `DefaultApi.GetAliases``: %v\n", err)
fmt.Fprintf(os.Stderr, "Full HTTP response: %v\n", r)
if apiErr, ok := err.(*onesignal.GenericOpenAPIError); ok {
// ErrorMessages() flattens any error-envelope shape to a []string;
// the raw body remains on Body().
fmt.Fprintf(os.Stderr, "Error Messages: %v\n", apiErr.ErrorMessages())
fmt.Fprintf(os.Stderr, "Response Body: %s\n", apiErr.Body())
}
}
// response from `GetAliases`: UserIdentityBody
fmt.Fprintf(os.Stdout, "Response from `DefaultApi.GetAliases`: %v\n", resp)
}
- lang: ruby
label: Ruby SDK
source: |-
require 'onesignal'
# setup authorization
OneSignal.configure do |config|
# Configure Bearer authorization: rest_api_key
config.rest_api_key = 'YOUR_BEARER_TOKEN'
end
api_instance = OneSignal::DefaultApi.new
app_id = '00000000-0000-0000-0000-000000000000' # String |
alias_label = 'external_id' # String |
alias_id = 'YOUR_USER_EXTERNAL_ID' # String |
begin
result = api_instance.get_aliases(app_id, alias_label, alias_id)
p result
rescue OneSignal::ApiError => e
puts "Error when calling DefaultApi->get_aliases: #{e}"
puts "Status Code: #{e.code}"
# `e.error_messages` flattens any error-envelope shape to an Array;
# the raw body remains on `e.response_body`.
puts "Error Messages: #{e.error_messages}"
puts "Response Body: #{e.response_body}"
end
- lang: java
label: Java SDK
source: |-
// Import classes:
import com.onesignal.client.ApiClient;
import com.onesignal.client.ApiException;
import com.onesignal.client.Configuration;
import com.onesignal.client.auth.*;
import com.onesignal.client.model.*;
import com.onesignal.client.api.DefaultApi;
public class Example {
public static void main(String[] args) {
ApiClient defaultClient = Configuration.getDefaultApiClient();
defaultClient.setBasePath("https://api.onesignal.com");
// Configure HTTP bearer authorization: rest_api_key
HttpBearerAuth rest_api_key = (HttpBearerAuth) defaultClient.getAuthentication("rest_api_key");
rest_api_key.setBearerToken("BEARER TOKEN");
DefaultApi apiInstance = new DefaultApi(defaultClient);
String appId = "00000000-0000-0000-0000-000000000000"; // String |
String aliasLabel = "external_id"; // String |
String aliasId = "YOUR_USER_EXTERNAL_ID"; // String |
try {
UserIdentityBody result = apiInstance.getAliases(appId, aliasLabel, aliasId);
System.out.println(result);
} catch (ApiException e) {
System.err.println("Exception when calling DefaultApi#getAliases");
System.err.println("Status code: " + e.getCode());
// getErrorMessages() flattens any error-envelope shape to a List;
// the raw body remains on getResponseBody().
System.err.println("Error messages: " + e.getErrorMessages());
System.err.println("Reason: " + e.getResponseBody());
System.err.println("Response headers: " + e.getResponseHeaders());
e.printStackTrace();
}
}
}
- lang: csharp
label: C# SDK
source: |-
using System;
using System.Collections.Generic;
using System.Diagnostics;
using OneSignalApi.Api;
using OneSignalApi.Client;
using OneSignalApi.Model;
namespace Example
{
public class GetAliasesExample
{
public static void Main()
{
Configuration config = new Configuration();
config.BasePath = "https://api.onesignal.com";
// Configure Bearer token for authorization: rest_api_key
config.AccessToken = "YOUR_BEARER_TOKEN";
var apiInstance = new DefaultApi(config);
var appId = "00000000-0000-0000-0000-000000000000"; // string |
var aliasLabel = "external_id"; // string |
var aliasId = "YOUR_USER_EXTERNAL_ID"; // string |
try
{
UserIdentityBody result = apiInstance.GetAliases(appId, aliasLabel, aliasId);
Debug.WriteLine(result);
}
catch (ApiException e)
{
Debug.Print("Exception when calling DefaultApi.GetAliases: " + e.Message );
Debug.Print("Status Code: "+ e.ErrorCode);
// e.ErrorMessages flattens any error-envelope shape to an IReadOnlyList;
// the raw body remains on e.ErrorContent.
Debug.Print("Error Messages: " + string.Join(", ", e.ErrorMessages));
Debug.Print("Response Body: " + e.ErrorContent);
Debug.Print(e.StackTrace);
}
}
}
}
- lang: rust
label: Rust SDK
source: |-
use onesignal_rust_api::apis::configuration::Configuration;
use onesignal_rust_api::apis::default_api;
#[tokio::main]
async fn main() {
let mut configuration = Configuration::new();
configuration.rest_api_key_token = Some("YOUR_REST_API_KEY".to_string());
// Realistic values are pulled from the spec's `example:` fields where present.
let app_id: &str = "00000000-0000-0000-0000-000000000000";
let alias_label: &str = "external_id";
let alias_id: &str = "YOUR_USER_EXTERNAL_ID";
match default_api::get_aliases(&configuration, app_id, alias_label, alias_id).await {
Ok(resp) => println!("{:?}", resp),
Err(e @ onesignal_rust_api::apis::Error::ResponseError(_)) => {
// `e.error_messages()` flattens any error-envelope shape to a Vec;
// the raw response remains on the ResponseError variant.
eprintln!("get_aliases failed: {:?}", e.error_messages());
}
Err(e) => eprintln!("get_aliases failed: {:?}", e),
}
}
components:
schemas:
StructuredErrorResponse:
type: object
properties:
errors:
type: array
items:
$ref: '#/components/schemas/StructuredErrorItem'
BasicErrorResponse:
type: object
properties:
errors:
type: array
items:
type: string
description: One or more human-readable error messages.
success:
type: boolean
description: >-
Present (and `false`) on some endpoints (notifications, templates,
segments). Not emitted by every endpoint.
reference:
type: array
items:
type: string
description: >-
Documentation URL fragments related to the error. Only emitted by
the API-key auth error helpers.
StructuredErrorItem:
type: object
required:
- code
- title
properties:
code:
type: string
description: >-
Stable error-code identifier. Use this for programmatic branching in
your integration.
title:
type: string
description: >-
Human-readable error message intended for logs and operator-facing
surfaces.
meta:
type: object
additionalProperties: true
description: >-
Optional structured details about this specific error. The shape of
`meta` varies by `code` — for example, the create-user `Conflict`
code returns `{ conflicting_aliases: { [alias_label]: alias_id } }`.
````