# Additional charges on top of Subscriptions

You can charge customers on top of their monthly subscriptions. Think of this as a sort of Usage-Based Subscription where your API can instruct how much to charge the customer based on your own estimate of your software's usage like:

* Credits
* Data
* Storage
* API Calls

This charge will be added to an existing Subscription and will generate a separate invoice.

<figure><img src="/files/eFxEcPY5cJLrksPFa33N" alt=""><figcaption><p>Example Subscription with a custom charge (overcharge) on top of existing Subscription</p></figcaption></figure>

You can charge on top of existing Subscription using this [API endpoint](https://api.app.fungies.io/v0/api-docs/#/subscriptions/PostV0SubscriptionsSubscriptionIdOrNumberCharge):

<figure><img src="/files/V9HslAWxO0VdOyMkhhlm" alt=""><figcaption><p>API endpoint to charge any amount on top of existing Subscription</p></figcaption></figure>

You can charge as many time you want:

```
"description": "Transaction description",
"items": [{
 "name": "overusage A",
 "value": 200,
},{
 "name": "overusage B",
 "value": 500,
}] 
```

In above example, the customer will be charged with $2 for Overusage A and $5 for Overusage B.

There will be:

* Additional invoices generated for each Overusage / Charge above current Subscription
* History of all charges for certain Subscription can be seen from the Dashboard in Subscription details of the customer.


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