# Uptime Monitoring: Overview

Uptime Monitoring checks all day that your site answers. It records every outage, shows how fast your site answers, and tells you when your SSL certificate or your domain registration expires.

## How Uptime Monitoring works [#how-uptime-monitoring-works]

VitalSentinel sends a request to the address of your domain at a regular interval. It checks one page, from one place. Each request is a check. A check passes when your site answers. A check fails when the site sends an error, does not answer in time, or cannot be reached.

A run of failed checks is one outage. The outage starts at the first failed check and ends at the next successful check. A few minutes of downtime is normal. Long or repeated outages need attention.

How often VitalSentinel checks your site depends on your plan. The plan list on the billing page shows it. See [Plans and limits](/workspace/plans-and-limits).

### What Uptime Monitoring measures [#what-uptime-monitoring-measures]

- **Availability**: the share of checks that got an answer, and every outage.
- **Response time**: how long your site takes to answer a check.
- **SSL certificate**: who issued it and when it expires.
- **Domain registration**: when your domain name expires.

If [Web Analytics](/connect/analytics-script) is installed, Uptime Monitoring also estimates the visits, orders and revenue that each outage cost. If [Server Log Monitoring](/connect/server-logs) is connected, it shows what search and AI bots got during the outages.

## Before you start [#before-you-start]

- Uptime Monitoring needs no setup. The checks start when you verify your domain. See [Verify ownership](/getting-started/domain-setup/verify-ownership).
- To open it, select **Uptime Monitoring** in the **Crawling & availability** group of the domain sidebar.
- Everyone in the workspace sees the same data. Only owners and admins can use **Accept as up** and set up conversion tracking.

## The page header [#the-page-header]

The header of Uptime Monitoring shows a status chip:

| Chip | Meaning |
|------|---------|
| **Up · Checked** and a date | The last check passed. |
| **Down · Checked** and a date | The last check failed. Your site is down now. |
| **Not measured** | Your server refuses our checks, so VitalSentinel cannot tell if the site is up. |

## The tabs [#the-tabs]

Uptime Monitoring has three tabs:

- [Availability](/uptime-monitoring/availability): uptime, every outage, what the outages cost, and hours when Google got errors although the site looked up.
- [Response time](/uptime-monitoring/response-time): how fast your site answered, the slowest checks, and how fast it is for visitors and Googlebot.
- [SSL and domain](/uptime-monitoring/ssl-and-domain): your SSL certificate, your domain registration and the certificate changes.

## The filter bar [#the-filter-bar]

The filter bar of Uptime Monitoring holds the date range and the comparison. The **SSL and domain** tab has no filter bar, because the certificate and the domain show today's state.

The date range offers **Today**, **Yesterday**, **Last 7 days**, **Last 28 days**, **Last 30 days**, **Last 90 days**, **Last 6 months**, **Last 12 months**, **This year** and **Last year**. The default is **Last 28 days**. The range always ends today, so a new check shows at once. Today is a partial day.

On the **Availability** tab, the filter bar also has filters for the list of outages. See [Availability](/uptime-monitoring/availability#filter-the-outages).

## The verdict [#the-verdict]

The verdict of Uptime Monitoring is one sentence about the selected tab. It shows only when there is something to say. Examples on the **Availability** tab:

| Verdict | Meaning |
|---------|---------|
| **Your site is down right now** | An outage is in progress. The line says since when. |
| **The outages affected visitors** | Web Analytics estimates lost visits. The line gives the count. |
| **Search and AI bots got errors during the outages** | Server Log Monitoring found bot requests that got errors. |
| **The outages affected visitors and search and AI bots** | Both of the above. |
| **Your site looked up, but Google got errors** | Every check passed, but Googlebot or Search Console reported server errors. |
| **Google is still crawling less after an outage** | Google and AI bots have not returned to their usual crawl yet. |

On the **Response time** tab, the verdict can say **Answers were slow on** and the slow days. The line gives the slowest answer on those days and the typical answer.

## Notices at the top of the page [#notices-at-the-top-of-the-page]

### Open issues from Site Health Monitoring [#open-issues-from-site-health-monitoring]

If Site Health Monitoring found problems with your uptime, Uptime Monitoring shows a line such as **2 open issues from Uptime Monitoring**, with a count for each severity. Click **Open in Site Health Monitoring** to see the issues. See [Site Health Monitoring](/site-health/overview).

### Waiting for verification [#waiting-for-verification]

If Uptime Monitoring shows **Waiting for verification**, your domain is not verified. VitalSentinel checks nothing until you verify it. See [Verify ownership](/getting-started/domain-setup/verify-ownership).

### Uptime checks did not start [#uptime-checks-did-not-start]

If Uptime Monitoring shows **Uptime checks did not start**, VitalSentinel could not start to check your domain. Contact support from Theo. See [Support tickets](/theo/support-tickets).

### Not measured because your server refuses our checks [#not-measured-because-your-server-refuses-our-checks]

If your server or firewall turns our checks away, Uptime Monitoring shows a red notice. For example: **Not measured because your server refuses our checks (403 on 95% of them)**. The number is the status code that your server sent, and the share of checks it refused.

While this notice shows, VitalSentinel does not count the site as down. It shows no uptime figure and no outages until the checks get through. To fix it, allow our monitoring in your firewall or CDN. Use our user agent or our IP addresses. Click **How to allow our checks**, or see [Monitoring IP addresses](/help/monitoring-ips).

If your site refuses visitors on purpose, for example a staging site behind a login, owners and admins can turn on **Accept as up**. VitalSentinel then counts the site as up, and the uptime figure comes back.

## Troubleshooting [#troubleshooting]

### Why does Uptime Monitoring show no checks? [#why-does-uptime-monitoring-show-no-checks]

If Uptime Monitoring shows **No checks in this window**, no check ran in the date range. If the domain is not verified, the page shows **Waiting for verification**. Verify the domain to start the checks. If you selected a range before the domain was added, select a later range.

### How often is my site checked? [#how-often-is-my-site-checked]

The check interval depends on your plan. See [Plans and limits](/workspace/plans-and-limits). You cannot change the interval for one domain.

### Why does Uptime Monitoring say Not measured? [#why-does-uptime-monitoring-say-not-measured]

If the status chip says **Not measured**, your server refuses our checks. Allow our monitoring in your firewall or CDN. See [Monitoring IP addresses](/help/monitoring-ips). If the site refuses visitors on purpose, turn on **Accept as up**.

### How do I get an alert when my site goes down? [#how-do-i-get-an-alert-when-my-site-goes-down]

Set up an alert rule for Uptime Monitoring on the Alerts page of the domain. See [Alerts](/domain/alerts). You can also click **Set up an alert** in the **Alerts that fired** section of an outage.

## Related [#related]

- [Availability](/uptime-monitoring/availability) - uptime, outages and what they cost
- [Response time](/uptime-monitoring/response-time) - how fast your site answers
- [SSL and domain](/uptime-monitoring/ssl-and-domain) - certificate and domain expiry
- [Alerts](/domain/alerts) - get a message when your site goes down
- [Monitoring IP addresses](/help/monitoring-ips) - allow our checks in your firewall
- [Server Log Monitoring responses](/server-logs/responses) - what bots got from your server