Uptime Kuma Alternative: SensaCat
Uptime Kuma is free and excellent. It also runs on a server that can die without telling you.
SensaCat is the alternative if you want someone else responsible for keeping the monitor alive. Uptime Kuma is free, open source and genuinely good, and the real cost is not the licence, it is the operations.
Uptime Kuma details below reflect the project's README and release notes as of September 2026.
What Uptime Kuma does well
It is MIT-licensed, free forever, and has accumulated roughly 86,000 GitHub stars, which makes it the most popular self-hosted monitoring project by a wide margin. There are no monitor caps and no premium tier.
Monitor types cover HTTP(s), keyword, JSON query, WebSocket, TCP, ping, DNS record, push heartbeat, Docker containers and Steam game servers, with 20-second intervals and over 90 notification channels. Version 2.1 in February 2026 added domain expiry monitoring and Globalping probes.
It runs on SQLite in about 512MB of RAM. A $5 VPS handles it comfortably, and the push monitor type does exactly what a heartbeat monitor should.
The gap: who watches the watcher
This is the trade-off that every Uptime Kuma comparison should lead with and most do not. If the server running Uptime Kuma goes down, your monitoring goes down with it, and nothing is left to tell you that happened.
A monitoring tool hosted on the same infrastructure it monitors shares that infrastructure's failure modes. The outage you most need catching is the one that takes both down at once.
The rest of the cost is your time. You patch it, back up the SQLite file, handle upgrades across major versions, and make sure the notification channels still authenticate. That is a real recurring cost even if it never appears on an invoice.
On coverage, there is no credential or API-key expiry tracking, and no multi-step business process correlation. Certificate expiry is covered, domain expiry arrived in 2.1, but a lapsing OAuth token has nowhere to live.
Feature comparison
| Feature | Uptime Kuma | SensaCat |
|---|---|---|
| Cost | $0, MIT licensed | $0 Free tier, $24/mo Starter |
| Hosting | Self-hosted (your responsibility) | Managed |
| Survives your server going down | No | Yes |
| Check interval | 20 seconds | 5 minutes (Team), 15 minutes (Free/Starter) |
| Notification channels | 90+ | Email, Slack, Discord |
| Push / heartbeat monitoring | Yes | Yes, with grace periods and failure reporting |
| SSL certificate expiry | Yes | Yes |
| Domain expiry | Yes (since v2.1, Feb 2026) | Yes |
| Credential / API-key expiry | No | Yes |
| Multi-step business flows | No | Yes |
| Data stays on your infrastructure | Yes | No |
Who should stay on Uptime Kuma
Stay if you are already comfortable running infrastructure, if compliance requires data to stay inside your perimeter, or if you are monitoring internal services that a hosted tool cannot reach anyway. For homelabs and internal networks it is the correct answer.
The sensible hybrid is worth mentioning: run Uptime Kuma internally and point one external monitor at it, so something outside your perimeter notices when the watcher stops watching.
Switch if the maintenance has become a chore, or if expiry-shaped failures are the ones actually hurting you. Start free.