> For the complete documentation index, see [llms.txt](/llms.txt)

# GS2-Auth SDK for Game Engine API Reference

Specifications of models and API references for GS2-Auth SDK for Game Engine



## Models

### EzAccessToken

Access token

A model that manages access tokens issued after user authentication.
Access tokens are used to identify a session while a user is logged in to the service.
Tokens have an expiration time, and when they expire, re-authentication is required.

|  | Type | Condition | Required | Default | Value Limits | Description |
| --- | --- | --- | --- | --- | --- | --- |
| token | string |  | ✓ |  |  ~ 1024 chars | Access token<br>A token used to authenticate access.<br>This token is automatically generated by the system and identifies the user's session. |
| userId | string |  | ✓ |  |  ~ 128 chars | User ID |
| expire | long |  |  | Absolute time 1 hour after the current time |  | Expiration time<br>A timestamp indicating the expiration time of the token. When this date is reached, the token becomes invalid.<br>Unix time, milliseconds |


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## Methods

### login

Log in to GS2 using account credentials

Pass the `body` and `signature` obtained from [GS2-Account::Authentication](../../account/game_engine/#authentication) to log in and receive an `access token`.
The `access token` is a temporary login credential valid for 1 hour, and is required to use GS2 services as a specific player.

In most cases, you do not need to call this API directly.
The Unity and Unreal Engine 5 SDKs provide Profile::Login, which combines [GS2-Account::Authentication](../../account/game_engine/#authentication) and this API into a single call.
See [Initialization / Game Engine](../../initialize/game_engine/) for details.

#### Request

|  | Type | Condition | Required | Default | Value Limits | Description |
| --- | --- | --- | --- | --- | --- | --- |
| keyId | string |  | | "grn:gs2:{region}:{ownerId}:key:default:key:default" |  ~ 1024 chars | Encryption Key GRN |
| body | string |  | ✓|  |  ~ 524288 chars | Signed authentication payload |
| signature | string |  | ✓|  |  ~ 1024 chars | Signature |

#### Result

|  | Type | Description |
| --- | --- | --- |
| token | string | Access token<br>A token used to authenticate access.<br>This token is automatically generated by the system and identifies the user's session.|
| userId | string | User ID|
| expire | long | Expiration time<br>A timestamp indicating the expiration time of the token. When this date is reached, the token becomes invalid.<br>Unix time, milliseconds|

#### Implementation Example




**Unity (UniTask)**
```csharp
    var domain = gs2.Auth.AccessToken(
    );
    var result = await domain.LoginAsync(
        body: "body",
        signature: "signature",
        keyId: "key-0001"
    );
    var token = result.Token;
    var userId = result.UserId;
    var expire = result.Expire;

```

**Unity (Vanilla)**
```cs
    var domain = gs2.Auth.AccessToken(
    );
    var future = domain.LoginFuture(
        body: "body",
        signature: "signature",
        keyId: "key-0001"
    );
    yield return future;
    if (future.Error != null)
    {
        onError.Invoke(future.Error, null);
        yield break;
    }
    var token = future.Result.Token;
    var userId = future.Result.UserId;
    var expire = future.Result.Expire;

```

**Unreal Engine 5**
```cpp
    const auto Domain = Gs2->Auth->AccessToken(
    );
    const auto Future = Domain->Login(
        "body", // body
        "signature", // signature
        "key-0001" // keyId
    );
    Future->StartSynchronousTask();
    if (Future->GetTask().IsError())
    {
        return false;
    }
    const auto Result = Future->GetTask().Result();
    const auto Token = Result->Token;
    const auto UserId = Result->UserId;
    const auto Expire = Result->Expire;

```


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