Uptime monitoring that tells you before users do.
Monitor sites, APIs, certificates, redirects, DNS, and TCP ports. Route alerts to the right channel and publish status automatically.
No credit card · free plan · up and watching in minutes.
Outbound checks · we ping them
Inbound heartbeats · they ping us
Uptime · last 34 days
Live demo — Holter detects, alerts, and recovers on its own.
The problem
The status page says everything's fine while a support ticket — then another — tells a different story. By the time you notice from the inside, users have already noticed from the outside.
Set up in three steps
Add a monitor
Paste a URL and Holter checks it on a schedule — HTTP status, response body, SSL certificate, DNS, redirects, or a raw TCP port.
Choose where alerts go
Route alerts to email, Slack, Discord, or a webhook, immediate or batched.
Publish a status page
Turn on a public status page that updates automatically as incidents open and resolve.
What Holter does
Holter checks your endpoints on a schedule from outside your network — as often as every 60 seconds on Pro, every few minutes on Free. When a check fails, we open an incident, alert the right channel, and update your public status page automatically.
- ✓ Checks every 60 seconds on Pro, every 5 minutes on Free
- ✓ Status pages included
- ✓ Incident timeline for every outage
- ✓ Response-time tracking over time
Simple, transparent pricing
Free forever for up to 5 monitors. Pro unlocks 1-minute checks and more monitors from $15/mo.
Free plan needs no card. Every paid plan includes a 14-day free trial.
See full pricingQuestions, answered
As often as every 60 seconds on Pro, every 5 minutes on Free — you choose the schedule per monitor.
Websites and APIs (status, body, response time), SSL certificates, domains and DNS records, HTTPS redirects, and TCP ports.
No. The Free plan is free forever, no card required.
Yes — Slack, Discord, and webhooks are available in addition to email.
Uptime monitoring that tells you before users do.
No credit card required. Free plan available.
Start monitoring free