---
sourceDocument: Brazil IT Operations Management
sourceDocumentLink: https://www.servicenow.com/docs/r/it-operations-management

 Release :

    - brazil

ft:locale :

    - en-US

ft:publication_title :

    - Brazil IT Operations Management

ft:clusterId :

    - itom

bundleId :

    - itom

workflow :

    - Technology


---

# Metric rule rate limiting

# Metric rule rate limiting {#ariaid-title1}

Release version: Brazil  
Updated September 10, 2026  
![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read  
Rate limiting controls how many alerts metric and event rules can raise within a time window. DEX enforces a per-rule limit and a combined limit across all rules, so a single rule matching more devices or events than expected doesn't overwhelm alert processing.

A metric rule raises an alert every time its criteria are met. When a rule applies to many devices or applications, or when one condition affects many users, the rule might generate more alerts than your team can act on. Rate
limiting bounds that volume.

DEX counts the alert requests each rule makes during a window and compares that count against two separate limits. Both limits are enforced independently, and reaching either one
stops further alerts until the window closes.

Per-rule rate limit
:   Each metric rule and event rule carries its own limit. DEX tracks the alert count for a rule against the end of the current window. Rate limiting helps prevent one noisy rule from consuming the capacity that the rest of your
    rules need.

    The per-rule count resets when the window closes.

Total rate limit
:   The total rate limit applies to all metric rules and event rules combined. Even when no individual rule has reached its own limit, alert processing stops for the remainder of the window after the combined count reaches
    the total limit.

When the limit is reached, the alert rule is dropped and an error is recorded.

To set the limits, see [Configure rate limits for metric rules](https://www.servicenow.com/docs/c8ULTnEblhyewFvGM57v4w "Control alert volume by setting the maximum number of alerts a single metric or event rule can raise in a time window, and the total across all rules. Use rate limits to help prevent alert storms and keep processing within your instance capacity.").

A separate control caps how many metric rules you can create, rather than how many alerts they raise. For that control, see "Define threshold for handling user metric rules."

For general information about metric rules, see [Using alert rules for Digital End-User Experience](https://www.servicenow.com/docs/Jrt4EOJnKkxDPSu_~SZXlA "Alert rules set criteria and thresholds that trigger alerts when performance metrics and events deviate from specified parameters. Use these alerts to identify and address potential issues.").