--- title: "Uptime Monitoring" description: "Learn how to help maintain uptime for your web services by monitoring relevant URLs with Sentry's Uptime Monitoring." url: https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/ --- # Uptime Monitoring Sentry's Uptime Monitoring lets you monitor the availability and reliability of your web services effortlessly. Once enabled, it continuously tracks configured URLs, delivering instant alerts and insights to quickly identify downtime and troubleshoot issues. By leveraging [distributed tracing](https://docs.sentry.io/concepts/key-terms/tracing/distributed-tracing.md), Sentry enables you to pinpoint any errors that occur during an uptime check, simplifying triage and accelerating root cause analysis. This helps you enhance both the reliability and uptime of your web services. ## [Set Up](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#set-up) Uptime is [automatically configured](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/automatic-detection.md) as a new alert for the most frequently encountered hostname in all URLs of your error data, ensuring continuous monitoring of your most critical hostname right out of the box. You can also [create uptime monitoring alerts](https://docs.sentry.io/product/alerts/create-alerts.md) for specific URLs. They're fully customizable with request details such as the HTTP method, headers, and body. ## [Uptime Check Criteria](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#uptime-check-criteria) Our uptime monitoring system verifies the availability of your URLs by performing HTTP requests at regular, pre-configured intervals. For a URL to be considered up and running, the response must meet the following criteria: 1. **Successful Response (2xx Status Codes):** By default, the URL must return an HTTP status code in the 200–299 range, indicating a successful request. You can customize this behavior with [custom verification](https://docs.sentry.io/product/alerts/create-alerts/uptime-alert-config.md#5-verification) (early access). 2. **Automatic Handling of Redirects (3xx Status Codes):** Sentry will follow redirects for URLs returning an HTTP status code in the 300–399 range and verify that the final destination URL returns a successful response. This ensures that redirects won't falsely trigger downtime alerts. 3. **Timeout Setting:** Each request has a timeout threshold of 10 seconds. If the server doesn't respond within this period, the check will be marked as a failure, indicating a potential downtime or performance issues. 4. **DNS Issue Detection:** Our monitoring also includes the detection of DNS resolution issues. If a DNS issue is detected, the check will be marked as a failure, allowing you to address the underlying connectivity problems. ### [Uptime Check Failures](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#uptime-check-failures) An uptime alert continuously monitors the configured URL with the criteria defined above. If a failure occurs, a new [uptime issue](https://docs.sentry.io/product/issues/issue-details/uptime-issues.md) is created, including details about the failed check and related errors. To prevent false alerts caused by temporary network issues, **an issue is only generated after three consecutive failures** (configurable via [thresholds](https://docs.sentry.io/product/alerts/create-alerts/uptime-alert-config.md#4-thresholds)) following the initial detection of downtime. Additionally, uptime checks are performed from a variety of geographical locations in a round-robin fashion. This ensures that each failed check comes from a different region, reducing the likelihood of false positives due to localized network failures. *In rare cases where Sentry is unable to perform a scheduled uptime check—such as during outages—the check status will be marked as "Unknown".* ## [Uptime Request Spans](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#uptime-request-spans) Uptime checks include spans called *uptime request spans* that Sentry automatically creates for the request. The `uptime.request` span acts as a root span for traces related to uptime checks. **Key Benefits:** * Context: You instantly know a trace was generated by an uptime check vs user traffic * Request lifecycle: You can see the full journey from the initial uptime check through your application's response * Enhanced debugging: You can see more details about exactly where and why the failure occurred to distinguish between uptime-related issues and other application problems Uptime request spans are free and will not count against your [span quota](https://docs.sentry.io/pricing/quotas/manage-transaction-quota.md). These spans are always created, even if you have sampling disabled. ## [Notifications](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#notifications) To start getting notifications for a new downtime issue, [configure an issue alert](https://docs.sentry.io/product/alerts/create-alerts/issue-alert-config.md) and choose the issue category "outage". Then choose how you'd like to be notified (via email, Slack, and so on). ## [Learn More About Uptime Monitoring](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring.md#learn-more-about-uptime-monitoring) * #### [Automatic Detection](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/automatic-detection.md) Learn how automatic detection of uptime monitoring works. * #### [Distributed Tracing with Uptime](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/uptime-tracing.md) Learn how to use distributed tracing to troubleshoot downtime. * #### [Troubleshooting](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/troubleshooting.md) Learn how to troubleshoot potential Uptime Monitoring problems. ## Pages in this section - [Automatic Detection](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/automatic-detection.md) - [Distributed Tracing with Uptime](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/uptime-tracing.md) - [Troubleshooting](https://docs.sentry.io/product/new-monitors-and-alerts/monitors/uptime-monitoring/troubleshooting.md)