Uptime Monitoring
Monitor your website's availability 24/7 with instant alerts when issues occur.
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
VitalSentinel checks your website at regular intervals:
- Sends an HTTP/HTTPS request to your URL
- Measures response time
- Verifies the response is successful (2xx or 3xx status)
- Records the result
If a check fails, you're immediately notified.
Check Intervals
The frequency of uptime checks depends on your plan:
| Interval | Description |
|---|---|
| 1 minute | Fastest detection (Advanced plan) |
| 5 minutes | Standard (all plans) |
Available check frequencies depend on your plan.
Dashboard Overview
The uptime dashboard shows:
Status Indicator
- Up (green) - Site is up and responding
- Down (red) - Site is down or unreachable
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
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
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
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
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
Response Time
Time from request initiation to full response. The dashboard shows the median (p50) and 95th percentile (p95) response time across your selected time period.
Status Codes
- 2xx - Success
- 3xx - Redirect (followed automatically)
- 4xx - Client error (configuration issue)
- 5xx - Server error (downtime)
SSL Certificate
Monitored automatically:
- Issuer and validity
- Expiration date
- Chain validation
- Days until expiration alerts
Domain Registration
Monitored via WHOIS (for supported TLDs):
- Registration expiration date
- Days until expiration
- Registrar information
SSL Certificate Monitoring
VitalSentinel checks your SSL/TLS certificate regularly, independently of the uptime check interval:
Certificate Details
- Issuer - Certificate authority
- Valid From/To - Certificate validity period
- Days Until Expiration - Countdown to renewal
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 to configure certificate expiration alerts.
Certificate Errors
Detected issues include:
- Expired certificate
- Invalid chain
- Hostname mismatch
- Self-signed certificate
Domain Expiration Monitoring
VitalSentinel monitors when your domain registration expires using WHOIS data.
What's 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
| Days Until Expiry | Status |
|---|---|
| > 90 days | Green (healthy) |
| 30-90 days | Yellow (renew soon) |
| < 30 days | Red (urgent) |
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
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
If domain expiration checking isn't supported for your TLD, you'll see a notice explaining that public WHOIS data is not available.
Configuring Uptime Checks
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.
Available check frequencies depend on your plan.
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
What Triggers an Incident?
- HTTP status code 4xx or 5xx
- Connection timeout
- SSL/TLS errors
- DNS resolution failure
- Empty response
Incident Lifecycle
- Detected - A check fails after its in-check retries
- Open - Downtime is tracked from the first confirmed failure
- Resolved - A successful check ends the incident
- Documented - Duration and details recorded
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
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 for configuration details.
