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

# Overview

> Monitor your billing operations with Sentinel, Hyperline's real-time alerting system

Sentinel is Hyperline's built-in monitoring system. It continuously watches your billing operations and surfaces actionable alerts — called **tasks** — whenever something needs your attention, from failed payments to disconnected integrations.

<Note>
  The Sentinel panel is available only to users with the **View tasks** role. Within the panel, each user only sees the tasks and entities they have permission to access, based on their role.
</Note>

## How it works

Sentinel runs in the background and creates a task whenever it detects an issue in one of the monitored areas (payments, invoicing, subscriptions, quotes, or integrations). Tasks are deduplicated so you see a single rolled-up alert per issue category, with a count of affected entities.

Each task includes a short description, the number of affected entities (invoices, customers, subscriptions, etc.), and a link to the relevant list page so you can drill down and resolve the issue.

You can filter the list using the **All**, **Critical**, **High**, and **Moderate** tabs to focus on the most pressing issues first.

### Refreshing tasks

When you take an action that resolves part of a task, the task count and list of affected entities refresh automatically a few seconds later. If the count still looks out of date, you can trigger a manual refresh directly on the task.

## Monitored alerts

Sentinel monitors the following alerts, grouped by category:

### Payments

| Alert                                            | Description                                                                                             |
| ------------------------------------------------ | ------------------------------------------------------------------------------------------------------- |
| Invoice in error                                 | A payment attempt on an invoice has failed.                                                             |
| Customer with expired payment method             | The saved payment method has expired.                                                                   |
| Customer with payment method expiring soon       | The saved payment method is about to expire.                                                            |
| Payment method from a different invoicing entity | The customer's payment method belongs to a different invoicing entity than the one issuing the invoice. |
| Payment provider disconnected                    | A payment provider connection is no longer authorized.                                                  |
| Bank account failed to sync                      | Hyperline could not refresh transactions from a connected bank account.                                 |

### Invoicing

| Alert                             | Description                                                        |
| --------------------------------- | ------------------------------------------------------------------ |
| Invoice is late                   | An invoice has passed its due date without being paid.             |
| Invoice draft                     | A draft invoice is waiting to be finalized.                        |
| Electronic invoice failed to sync | An electronic invoice could not be delivered to the tax authority. |
| Customer has invalid tax ID       | The tax ID on the customer record failed validation.               |

### Quotes

| Alert                   | Description                                                       |
| ----------------------- | ----------------------------------------------------------------- |
| Quote activation failed | A quote was accepted but could not be turned into a subscription. |

### Subscriptions

| Alert                       | Description                                                           |
| --------------------------- | --------------------------------------------------------------------- |
| Subscription is errored     | The subscription is in an error state and is not billing as expected. |
| Subscription renewal failed | Automatic renewal of a subscription did not complete.                 |

### Integrations

| Alert                             | Description                                                       |
| --------------------------------- | ----------------------------------------------------------------- |
| Integration disconnected          | A third-party integration lost its authorization.                 |
| Integration setup error           | A newly added integration could not finish setup.                 |
| Integration needs reconfiguration | An existing integration requires updated credentials or settings. |
| Issue with integration            | The integration sync produced an error.                           |
| Data loader failed to sync        | A usage data loader could not refresh data.                       |

## Settings

Open the Sentinel settings to control which alerts are surfaced. Each alert can be individually enabled or disabled, which is useful for issues that don't apply to your setup — for example, hiding electronic invoice alerts if you don't issue them. Disabled alerts won't be created or shown in your task list.