> ## Documentation Index > Fetch the complete documentation index at: https://docs.flexprice.io/llms.txt > Use this file to discover all available pages before exploring further. # Low Balance Alert > Configure Wallet Sentinel Alerts to get notified when a customer's wallet balance crosses configurable Info, Warning, or Critical thresholds. Wallet Sentinel Alerts in Flexprice let you monitor wallet balance with **three alert levels** so you can act before balance becomes critical. You can enable or disable alerts per wallet and set a custom threshold for each level. **Benefits:** * **Proactive management**: Get notified at Info and Warning levels before balance reaches critical * **Granular control**: Separate thresholds for informational, warning, and critical states * **Absolute or percentage**: Set thresholds as a fixed amount or as a share of granted credits * **Per-wallet settings**: Enable or disable alerts and configure thresholds per wallet ## Threshold Types Every threshold is read either as an **Absolute** amount or as a **Percentage**. The threshold type applies to all three levels together. | | Absolute | Percentage | | - | - | - | | **A threshold of `10` means** | 10 in the customer's wallet currency | 10% of granted credits | | **Measured against** | The wallet balance itself | Credits granted in the current billing period | | **Accepted values** | Any amount, including negative | 0 to 100 | ### Absolute Thresholds Thresholds are fixed amounts denominated in the customer's wallet currency. On a USD denominated wallet, a Critical threshold of `10` triggers when the balance falls below \$10. Use **Absolute** when the threshold you care about is a specific fixed value, such as a minimum balance before service is interrupted or the level at which a top-up should be triggered. Negative values are allowed, so a post-paid wallet can alert on how far below zero it has gone. Absolute is the default. A wallet or tenant configuration saved without a threshold type is read as Absolute. ### Percentage Thresholds Thresholds are specified as a percentage of the credits granted during the customer's current billing period. A Critical threshold of `10` triggers when the ongoing balance falls below 10% of the credits granted in that billing period. If the customer has no active subscription, the wallet's total lifetime credits granted is used as the reference amount. Use Percentage when the meaningful floor scales with the customer. 20% left means the same thing to a customer granted 500 credits and one granted 50,000, where a fixed amount would not. Values must be between 0 and 100. Percentage threshold type selected, with each level shown as a percentage Percentage thresholds are calculated by expressing the [ongoing balance](/docs/wallet/balance-types#ongoing-balance) as a percentage of the credits granted for the current billing period. The ongoing balance reflects the real-time balance after accounting for current usage. ## Alert Levels | Level | Purpose | | - | - | | **Info** | Informational alert when balance crosses a defined threshold | | **Warning** | Early warning level before critical | | **Critical** | Critical alert level requiring immediate action | Each level takes a single **threshold value**, read according to the configured [threshold type](#threshold-types). An alert triggers when the balance falls below that value. Configure only the levels you need, subject to two rules: a critical threshold is required when a warning threshold is set, and thresholds must ascend by severity, so critical is lower than warning and warning is lower than info. Alerts are turned on or off for a wallet using **Enable wallet alerts** (`alert_enabled` in the API). ## Configuring Wallet Sentinel Alerts * Go to **Billing** in the main navigation * Select **Customers**, then the desired customer * Open the **Wallet** tab in the customer profile * Click the **three-dot menu (⋮)** in the top right corner of the wallet section * Select **Alert Settings** from the dropdown Access Alert Settings In the **Wallet Alert Settings** dialog, turn **Enable wallet alerts** on to activate monitoring against your configured thresholds. Enable Alert Settings * Choose **Absolute** or **Percentage** under **Threshold type**. * Set a value for the levels you want. Each level triggers when its threshold is breached. * Click **Save Changes** to apply. Configure Alert Settings ## Alert Behavior Once configured and enabled, the sentinel will: * **Monitor balance**: Evaluate wallet balance against your thresholds (e.g. after top-ups, debits, and accounting for usage) * **Trigger by level**: Raise **Info**, **Warning**, or **Critical** alert based on which threshold is crossed * **Update state**: Reflect current state (e.g. ok, info, warning, in\_alarm) on the wallet and in alert history * **Notify**: Send webhooks when alert state changes Webhooks are sent when alert state changes (e.g. ok → warning, warning → in\_alarm). Configure your webhook endpoint to receive these notifications. ## Managing Alert Settings ### Viewing Current Configuration Open the customer’s **Wallet** tab, click the **three-dot menu (⋮)** → **Alert Settings**. The dialog shows **Enable wallet alerts**, the selected **Threshold type**, and the threshold levels with their values. ### Changing Thresholds In the **Alert Settings** dialog box, adjust **Enable wallet alerts**, the **Threshold type**, or any threshold value, then click **Save Changes** to apply. ### Disabling Alerts Set **Enable wallet alerts** to **off** in the **Alert Settings** dialog and click **Save Changes** (or set `alert_enabled` to `false` via API). The wallet will no longer generate real time balance alerts until you enable them again. ## Use Cases ### SaaS and Usage-Based Billing * **Low balance warnings**: Critical at 0, Warning at 5, Info at 10 so you get early notice and can top up before going negative * **Prepaid credits**: notify when credits are running low at multiple levels to avoid running out of credits unexpectedly * **Service Continuity**: Prevent service interruptions due to insufficient funds ### E-commerce Platforms * **Wallet monitoring**: different severities for different teams or workflows * **Promotional or prepaid wallets**: alerts when balance is low relative to typical usage * **Payment Processing**: Ensure sufficient funds for transactions ### API and Credit-Based Products * **Usage vs balance**: early Info/Warning so support or automation can act before Critical * **Multi-wallet**: per-wallet sentinel settings so each wallet has its own thresholds * **Rate Limiting**: Prevent service disruption due to insufficient credits * **Customer Support**: Proactive customer communication ## Best Practices 💡 **Set realistic thresholds**: choose values that give enough time to top up (e.g. Warning above zero if you want to avoid negative balance) 💡 **Use all three levels**: use Info for early notice, Warning for action soon, Critical for immediate action 💡 **Pick the right threshold type**: use Absolute for a fixed floor in the wallet's currency, and Percentage when the meaningful floor scales with how many credits the customer was granted 💡 **Review periodically**: adjust thresholds based on usage patterns and top-up behavior 💡 **Combine with auto top-up**: use sentinel alerts together with auto top-up so critical levels can trigger automatic top-up when configured This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.