Synthetic Monitoring Tools

Your internal metrics say everything's fine.Your users disagree.

Synthetic monitoring checks your endpoints from outside your infrastructure. Like a user would. Before they complain.

25 monitors free. No credit card required.

uptimesignal — synthetic checks 
[US] app.yourapp.com        200 OK   (142ms)
[EU] app.yourapp.com        200 OK   (189ms)
[US] api.yourapp.com        Timeout  (30000ms)
  → Alert sent to [email protected]
External
Check location
1 min
Check interval
<2 min
Alert delivery

What is synthetic monitoring?

Synthetic monitoring simulates user interactions by sending requests to your endpoints from external locations. Instead of waiting for real users to encounter problems, synthetic monitoring proactively tests your services on a schedule.

Think of it as having a robot user that constantly checks if your site is working — from outside your network, exactly like your real users would access it.

Synthetic vs Real User Monitoring (RUM)

Synthetic Monitoring

  • ✓ Proactive — catches issues before users
  • ✓ Consistent test conditions
  • ✓ Works 24/7, even with no traffic
  • ✓ Tests specific endpoints

Real User Monitoring

  • ✓ Shows actual user experience
  • ✓ Captures real-world variations
  • ✓ Requires user traffic
  • ✓ Broader coverage

Both are valuable. Synthetic catches problems early. RUM shows you what users actually experience.

UptimeSignal is synthetic monitoring. We check your endpoints before your users do.

See all your endpoints at a glance

Status, response times, uptime history. One dashboard.

UptimeSignal Dashboard showing endpoint monitors with status indicators, response times, and uptime bars

Why external monitoring matters

Instant alerts everywhere

Email, Slack, Discord, Telegram, and webhook alerts within 60 seconds of detecting failures. Recovery alerts when you're back online.

CDN & DNS issues

Your server is fine, but users can't reach it. DNS propagation delays, CDN misconfigurations, routing problems — you'd never know from inside your network.

SSL certificate problems

Expired certificates, misconfigured chains, renewal failures. Your internal tools might skip SSL validation. Users' browsers don't.

Routing failures

Works from your office, fails for users elsewhere. Load balancer misconfigurations, regional outages, peering issues.

Internal monitoring tells you your servers are running. Synthetic monitoring tells you users can actually reach them.

How it works

1

Add your endpoints

https://app.yourapp.com

Any URL you want to monitor. Websites, APIs, webhooks.

2

We check from outside

✓ External request sent every minute
✓ SSL certificate validated
✓ Response time measured
3

Get alerted when it fails

✗ app.yourapp.com — Timeout

Email, Slack, Discord, Telegram, or webhook — within 2 minutes.

What we check

HTTP status codes

Detect 4xx and 5xx errors before your users do.

Response times

Catch slowdowns before they become outages.

SSL certificates

Get warned before your SSL expires.

Connection errors

DNS failures, refused connections, network issues.

Timeouts

Endpoints that hang without responding.

TLS handshakes

Certificate chain and protocol issues users see.

Simple pricing

No per-monitor fees. Unlimited monitors for $15/month.

Free

Get started with essentials

  • 25 monitors
  • 5-minute checks
  • Unlimited status pages
  • All integrations
  • Commercial use OK
Start free
$15 /month

For serious monitoring

  • Unlimited monitors
  • 1-minute checks
  • Unlimited status pages
  • All integrations
  • 90-day history
Start free, upgrade anytime

FAQ

What is synthetic monitoring?
Synthetic monitoring simulates user interactions by sending requests to your endpoints from external locations. Unlike real user monitoring (RUM) which tracks actual user sessions, synthetic monitoring proactively tests your services before users encounter problems.
What's the difference between synthetic and real user monitoring?
Synthetic monitoring proactively checks your endpoints on a schedule from external locations. Real user monitoring (RUM) passively tracks actual user sessions. Synthetic catches issues before users do; RUM shows you what users actually experience. Both are valuable for different purposes.
Where do you check from?
We check from outside your infrastructure using Cloudflare's global edge network, simulating real user access to your endpoints.
Do you check SSL certificates?
Yes. We verify SSL certificates during every check and will alert you if your certificate is invalid, expired, or about to expire.
Can I use the free plan commercially?
Yes. Commercial use is allowed on all plans, including Free. No restrictions.

Start monitoring from outside

25 monitors free. No credit card required.

We'll send you a magic link. No password to forget.

Also see: API Monitoring