What is website uptime monitoring?

Website uptime monitoring is the continuous automated testing of your website or API endpoints to detect downtime, slow response times, SSL certificate issues, DNS failures, and content errors. Sentinel monitors from 8 global regions every 60 seconds to give you the most accurate picture of your site's real-world availability.

How does Sentinel eliminate false positive uptime alerts?

Sentinel uses a quorum-based detection model — checks run from multiple independent geographic regions simultaneously. An incident only opens when a configurable quorum of regions agrees on the failure. A single regional network blip, a CDN hiccup, or a flaky hop never pages your on-call team.

What types of monitoring does Sentinel support?

Sentinel supports five check types: DNS monitoring (records, propagation, resolver consistency), HTTP monitoring (status codes, response time, redirect chains), SSL/TLS certificate monitoring (expiry alerts, chain trust, HSTS), Content monitoring (keyword detection, hash drift, parking page detection), and Browser synthetic monitoring (full Chromium rendering, JavaScript execution, MetaMask/Web3 detection).

Website Monitoring · Invite-only Beta

Know the second your
website goes down.

The website uptime monitoring tool that eliminates false positives. Distributed checks across 8 global regions — an alert only fires when a quorum of independent regions agrees. Real signal, zero noise.

Start monitoring free See all features

Multi-region quorum detection — single-region blips never page your on-call
DNS, HTTP, SSL certificate, content & browser checks — all in one platform
Instant downtime alerts via Email, Slack, Telegram & webhook with delivery proof

99.97%avg website uptime

<38smean time to alert

8global check regions

0false positives

Trusted by infrastructure teams monitoring 10,000+ domains globally

All regions healthy

quorum · 7/8 passing

0 false alerts · last 30d

8 regions

Global uptime checks

Enterprise-grade security on every plan — uptime monitoring you can trust

AES-256-GCM at rest
TOTP 2FA + recovery codes
RBAC · 4 permission levels
Double-submit CSRF guard
Append-only audit log
8 independent check regions
Quorum false-positive blocker

Features

Everything an SRE team needs. Nothing they don't.

Sentinel is built around the operations workflows that actually matter when something is on fire — and stays out of the way the rest of the time.

🔍

Five check types, one workflow

DNS, HTTP, SSL, content keyword, and headless browser checks. Configure once, watch everywhere.

🌍

Multi-region quorum detection

Checks run from 8 regions. An incident only opens when a configurable quorum agrees — single-region blips never wake your on-call.

🔔

On-call-grade alerting

Acknowledge, snooze, escalate, with critical-bypass routing. Email, Slack, Telegram, webhook — all delivery is logged and replayable.

📋

Forensics, not noise

Every check, every notification, every operator action lands in the append-only audit log. Find out what happened — and exactly who knew when.

🛡️

Security as a default

TOTP 2FA, recovery codes, RBAC across four roles, double-submit CSRF, AES-GCM at rest. The boring parts done right.

📊

SLO-first dashboards

Uptime, latency, MTTA / MTTR — surfaced where you need them. Drill from a region heatmap into the exact failed probe in two clicks.

How it works

From domain list to first uptime alert in under five minutes.

Set up comprehensive website monitoring — DNS, HTTP, SSL, content, and browser checks — without reading a manual.

step 01

Add your domains

Paste a list of hostnames or import from your DNS provider. Sentinel auto-discovers DNS records, SSL certificate expiry dates, and live HTTP endpoints — your website monitoring coverage is ready in seconds.

DNS records auto-discoveredSSL expiry trackedHTTP endpoints mapped

step 02

Configure your monitoring checks

Choose from DNS monitoring, HTTP uptime checks, SSL certificate tracking, content detection, or headless browser synthetic tests. Set check regions, cadence, and quorum threshold — intelligent defaults mean zero manual tuning to get started.

5 check types8 global regionsQuorum threshold control

step 03

Get instant downtime alerts — only when it's real

Route website downtime alerts to Email, Slack, Telegram, or webhook. Snooze during maintenance windows, acknowledge incidents, escalate to escalation contacts. Critical endpoints bypass quiet hours automatically.

Instant downtime alertsCritical bypass routingDelivery proof per alert

Use cases

Every team needs uptime monitoring. Not every team needs it the same way.

Sentinel adapts to your operational workflow — whether you're an SRE fighting alert fatigue, a SaaS team tracking customer-facing uptime SLAs, or a compliance team building audit trails.

DevOps & SRE Teams

Website uptime monitoring without on-call burnout

Quorum-based detection across 8 regions silences single-region noise and BGP blips
Snooze monitoring during planned maintenance, auto-resume when the window ends
Per-channel routing: page primary on-call for critical, Slack for informational
p50/p95/p99 latency tracking on every HTTP check — catch degradation before downtime

SaaS & Product Teams

Monitor what your customers actually experience

Browser synthetic monitoring for real JavaScript-rendered user journeys, not just ping checks
Content anomaly detection: catch "the page loads but the data is wrong" before users do
SSL certificate expiry alerts 30/14/7 days out — renew before it becomes an incident
DNS drift detection catches misconfigurations and CDN changes across all regions instantly

Compliance & SLO Management

Audit-ready uptime monitoring by default

Append-only audit log — every config change, every acknowledgement, immutable and timestamped
Per-domain SLO dashboards with MTTA, MTTR, and configurable uptime percentage windows
Exportable incident timelines with full evidence for post-mortems and compliance reviews
Role-based access control (RBAC) with four permission levels: Owner, Admin, Editor, Viewer

Why teams switch

The uptime monitoring defaults that make on-call actually sustainable.

Most website monitoring tools were built to detect — Sentinel was built to operate. Teams switching from Pingdom, UptimeRobot, or Datadog synthetic monitoring find the difference immediately: fewer pages, more context, full evidence.

Capability

Traditional monitoring tool

Sentinel

False positive uptime alerts
Single-region trigger pages on-call
Multi-region quorum required — zero noise
Acknowledge an incident
Hidden deep in sub-menus
Top of every alert and dashboard
SSL certificate monitoring
Separate tool or add-on required
Built-in, auto-tracked on every domain
Notification delivery proof
"Did the alert even fire?"
Every send logged and replayable
Website audit trail
"Available on Enterprise only"
Append-only audit log, day one, all plans
Quiet hours for on-call
All-or-nothing — critical or not
Critical bypass per-channel, configurable
Response time monitoring
Optional paid extra
p50/p95/p99 latency on every HTTP check
Browser synthetic monitoring
Separate product, extra cost
Built-in Chromium checks, same platform
Incident evidence
Log entry only
Screenshot + SSL cert + full response chain

Looking for a Pingdom alternative or UptimeRobot alternative? Sentinel adds quorum detection, browser synthetic checks, and forensic evidence — all in one platform.

check types

DNS · HTTP · SSL · Content · Browser (synthetic)

Five independent monitoring signals — from DNS propagation to headless browser rendering

global regions

EU · US East · US West · AP · ME · AU · SA · AF

Quorum-based detection across 8 independent geographic monitoring regions

60s

min check interval

Team & Enterprise plans · configurable per domain

Down to 60-second check intervals for time-critical uptime SLAs

∞

audit history

Append-only · immutable · exportable · always on

Every check, alert, and operator action preserved forever with full timestamps

sentinel.app · free during beta · invite-only

The website uptime monitoring tool that earns every alert it sends.

Add your domains, choose DNS, HTTP, SSL, or browser checks, and let 8 independent regions build the quorum that separates real incidents from regional noise. Full forensic evidence on every failure — screenshots, response chains, SSL details.

Start monitoring free Talk to the team

Quorum detection — zero false-positive alerts
8 independent global monitoring regions
AES-GCM encrypted · 2FA · RBAC
Free Starter plan · invite-only beta

Know the second your website goes down.