# Uptime Monitoring



Uptime monitoring continuously checks if your website is accessible and responsive. Get instant alerts when your site goes down and track historical availability.

## How It Works [#how-it-works]

VitalSentinel checks your website at regular intervals:

1. Sends an HTTP/HTTPS request to your URL
2. Measures response time
3. Verifies the response is successful (2xx or 3xx status)
4. Records the result

If a check fails, you're immediately notified.

## Check Intervals [#check-intervals]

The frequency of uptime checks depends on your plan:

| Interval  | Description                       |
| --------- | --------------------------------- |
| 1 minute  | Fastest detection (Advanced plan) |
| 5 minutes | Standard (all plans)              |

<Callout type="info">
  Available check frequencies depend on your plan.
</Callout>

## Dashboard Overview [#dashboard-overview]

The uptime dashboard shows:

### Status Indicator [#status-indicator]

* **Up (green)** - Site is up and responding
* **Down (red)** - Site is down or unreachable

### Uptime Percentage [#uptime-percentage]

Your availability over the selected period:

* 99.9% = \~43 minutes downtime/month
* 99.5% = \~3.6 hours downtime/month
* 99.0% = \~7.3 hours downtime/month

### Response Time Breakdown [#response-time-breakdown]

The response-time chart breaks each check into the stages before the first byte arrives: DNS lookup, connection, TLS handshake, and server wait. This shows where the time goes, not just the total.

### Incidents [#incidents]

Every outage in the selected window is listed with its start and end time, duration, and status code or error. When the Web Analytics module is installed, each incident also shows what it cost you in lost visitors and revenue (see Cost of Downtime below).

### Slow Checks [#slow-checks]

The slowest successful checks in the window (roughly the slowest 5%). The site stayed up, but a real visitor would have felt the lag.

### Cost of Downtime [#cost-of-downtime]

When the Web Analytics module is installed and configured, VitalSentinel estimates what outages cost you in lost sessions, lost orders, and lost revenue by comparing each outage window against a typical same weekday.

## Metrics Tracked [#metrics-tracked]

### Response Time [#response-time]

Time from request initiation to full response. The dashboard shows the &#x2A;*median (p50)** and &#x2A;*95th percentile (p95)** response time across your selected time period.

### Status Codes [#status-codes]

* **2xx** - Success
* **3xx** - Redirect (followed automatically)
* **4xx** - Client error (configuration issue)
* **5xx** - Server error (downtime)

### SSL Certificate [#ssl-certificate]

Monitored automatically:

* Issuer and validity
* Expiration date
* Chain validation
* Days until expiration alerts

### Domain Registration [#domain-registration]

Monitored via WHOIS (for supported TLDs):

* Registration expiration date
* Days until expiration
* Registrar information

## SSL Certificate Monitoring [#ssl-certificate-monitoring]

VitalSentinel checks your SSL/TLS certificate regularly, independently of the uptime check interval:

### Certificate Details [#certificate-details]

* **Issuer** - Certificate authority
* **Valid From/To** - Certificate validity period
* **Days Until Expiration** - Countdown to renewal

### Expiration Alerts [#expiration-alerts]

Set up alerts to get notified before your certificate expires. Available preset thresholds:

* 14 days before expiration (warning)
* 7 days before expiration (critical)

See [Setting Up Alerts](/alerts/setting-up-alerts) to configure certificate expiration alerts.

### Certificate Errors [#certificate-errors]

Detected issues include:

* Expired certificate
* Invalid chain
* Hostname mismatch
* Self-signed certificate

## Domain Expiration Monitoring [#domain-expiration-monitoring]

VitalSentinel monitors when your domain registration expires using WHOIS data.

### What's Tracked [#whats-tracked]

* **Days Until Expiry** - Countdown to domain expiration
* **Expiration Date** - When your domain registration ends
* **Registrar** - Your domain registrar
* **TLD** - Top-level domain

### Status Indicators [#status-indicators]

| Days Until Expiry | Status              |
| ----------------- | ------------------- |
| > 90 days         | Green (healthy)     |
| 30-90 days        | Yellow (renew soon) |
| \< 30 days        | Red (urgent)        |

### Supported TLDs [#supported-tlds]

Domain expiration checking uses public WHOIS data. The following TLDs are supported:

**Generic TLDs:**
.com, .net, .org, .info, .biz, .us, .co, .me, .io, .tv, .cc, .ws, .mobi, .name, .asia, .tel, .pro, .travel, .xxx, .ai, .agency

**New gTLDs:**
.xyz, .online, .tech, .store, .site

**Country TLDs with WHOIS support:**
.fr (France), .it (Italy), .pl (Poland), .cz (Czech Republic), .sk (Slovakia), .cn (China), .ru (Russia)

### Unsupported TLDs [#unsupported-tlds]

Many country-code TLDs don't provide public WHOIS data due to privacy regulations:

.eu, .de, .es, .uk, .co.uk, .jp, .nl, .be, .at, .ch, .dk, .se, .no, .fi, .ca, .au, .nz, .hk, .sg, .kr, .tw, .in, .br, .mx

<Callout type="info">
  If domain expiration checking isn't supported for your TLD, you'll see a notice explaining that public WHOIS data is not available.
</Callout>

## Configuring Uptime Checks [#configuring-uptime-checks]

### Check Interval [#check-interval]

The check interval is determined by your plan: every 5 minutes on all plans, and as often as every 1 minute on the Advanced plan. Higher-tier plans check more frequently for faster detection.

<Callout type="info">
  Available check frequencies depend on your plan.
</Callout>

### Request Timeout [#request-timeout]

Each uptime check has a timeout of 10 seconds. If your server doesn't respond within this time, the check is marked as failed.

## Incident Detection [#incident-detection]

### What Triggers an Incident? [#what-triggers-an-incident]

* HTTP status code 4xx or 5xx
* Connection timeout
* SSL/TLS errors
* DNS resolution failure
* Empty response

### Incident Lifecycle [#incident-lifecycle]

1. **Detected** - A check fails after its in-check retries
2. **Open** - Downtime is tracked from the first confirmed failure
3. **Resolved** - A successful check ends the incident
4. **Documented** - Duration and details recorded

### False Positives [#false-positives]

VitalSentinel minimizes false positives by:

* Retrying transient failures within a single check (up to 3 retries)
* Pausing alerts when many domains fail at once (mass-failure detection catches monitoring-side network issues)

## Alerts [#alerts]

Set up notifications for uptime events. Available alert presets:

* **Site is down** - Get notified when your site becomes unreachable
* **Site is up** - Get notified when your site recovers after downtime
* **SSL expiring** - 14 or 7 days before expiration
* **Domain expiring** - 14 or 7 days before expiration

See [Setting Up Alerts](/alerts/setting-up-alerts) for configuration details.

## Related Features [#related-features]

<Cards>
  <Card title="Setting Up Alerts" href="/alerts/setting-up-alerts">
    Get notified when issues occur
  </Card>

  <Card title="RUM Monitoring" href="/features/rum-monitoring">
    Track real user performance
  </Card>

  <Card title="Synthetic Monitoring" href="/features/synthetic-monitoring">
    Run on-demand performance tests
  </Card>
</Cards>