> ## Documentation Index
> Fetch the complete documentation index at: https://docs.particle.pro/llms.txt
> Use this file to discover all available pages before exploring further.

# add_on_required

> Feature requires purchasing an add-on package

export const BillingLink = ({children}) => {
  return <a href="https://platform.particle.pro/billing">{children}</a>;
};

|                    |                        |
| ------------------ | ---------------------- |
| **HTTP status**    | `402 Payment Required` |
| **Error code**     | `add_on_required`      |
| **Resolve action** | `purchase_add_on`      |

## What happened

The organization tried to use a feature beyond its plan's included allowance — for example, creating an alert when all of the plan's included alert slots are already in use.

The plan's allowance can be extended by purchasing add-on packages: each Alerts Pack add-on increases the alert allowance by five.

## How to fix

Purchase the required add-on via the platform UI's <BillingLink>billing page</BillingLink>, or call the add-on endpoint directly:

```
POST /v1/organizations/{org_id}/billing/addons
{
  "type": "monitor_pack",
  "quantity": 1
}
```

After the purchase succeeds, retry the original request.