# Set User Id

Once your user is logged in and you can send us a userId, please do it otherwise the purchase will be tied to the device and your user won't be able to enjoy from another device. Setting it will allow you to tie a purchase to a user to use it on other devices.

This ID will be passed to the Webhook so that your backend can identify the user and unlock the access.\
If our backend made a migration of user purchases and notified your backend, we will set the refresh variable in the callback to true.

{% tabs %}
{% tab title="Swift" %}

```swift
Purchasely.userLogin(with: "123456789")
```

{% endtab %}

{% tab title="Objective-C" %}

```objectivec
[Purchasely userLoginWith:@"123456789"];
```

{% endtab %}

{% tab title="Kotlin" %}

```kotlin
Purchasely.userLogin("123456789") { refresh ->
    if (refresh) {
        //you can call your backend to refresh user information
    }
}
```

{% endtab %}

{% tab title="Java" %}

```java
Purchasely.userLogin("123456789", refresh -> {
    if(refresh) {
        //you can call your backend to refresh user information
    }
    return null;
});
```

{% endtab %}

{% tab title="React Native" %}

```javascript
Purchasely.userLogin('123456789').then((refresh) => {
  if (refresh) {
    //call your backend to refresh user information
  }
});
```

{% endtab %}

{% tab title="Cordova" %}

```javascript
Purchasely.userLogin('user_id', refresh => { 
    if(refresh) {
        // You can call your back-end to refresh user information
    }  
});
```

{% endtab %}

{% tab title="Flutter" %}

```dart
Purchasely.userLogin('123456789').then((refresh) => {
  if (refresh) {
    //call your backend to refresh user information
  }
});
```

{% endtab %}

{% tab title="Unity" %}

```csharp
private PurchaselyRuntime.Purchasely _purchasely;

_purchasely.UserLogin("userId", OnUserLoginCompleted);
```

{% endtab %}
{% endtabs %}

To remove the user (logged out) you can perform a :

{% tabs %}
{% tab title="Swift" %}

```swift
Purchasely.userLogout()
```

{% endtab %}

{% tab title="Objective-C" %}

```objectivec
[Purchasely userLogout];
```

{% endtab %}

{% tab title="Kotlin" %}

```kotlin
Purchasely.userLogout()
```

{% endtab %}

{% tab title="Java" %}

```java
Purchasely.userLogout();
```

{% endtab %}

{% tab title="React Native" %}

```javascript
Purchasely.userLogout();
```

{% endtab %}

{% tab title="Cordova" %}

```javascript
Purchasely.userLogout()
```

{% endtab %}

{% tab title="Flutter" %}

```dart
Purchasely.userLogout();
```

{% endtab %}

{% tab title="Unity" %}

```csharp
private PurchaselyRuntime.Purchasely _purchasely;

_purchasely.UserLogout();
```

{% endtab %}
{% endtabs %}

{% hint style="warning" %}
If you allow logged out / anonymous users to make purchases, please [follow these steps](https://purchasely.gitbook.io/purchasely/advanced-features/anonymous-user)
{% endhint %}