--- title: "Best Open-Source Website Monitoring 2026: 7 Self-Host Picks" description: "We benchmarked 7 open-source website monitoring tools in May 2026. Best overall: Uptime Kuma (MIT). Best observability: SigNoz (MIT). Best YAML-native: Gatus…" canonical: "https://lemwatch.com/best/open-source-website-monitoring" source: "https://lemwatch.com" --- # Best Open-Source Website Monitoring Tools (2026): 7 Tested > Best open-source website monitoring in May 2026: Uptime Kuma (MIT, Docker, 5-min setup). For full observability, SigNoz (MIT, OpenTelemetry-native). For YAML-driven config, Gatus (Apache 2.0). All seven are genuinely open licences — not source-available. **Real OSS picks: Uptime Kuma (MIT, simplest), SigNoz (MIT, full observability), Gatus (Apache 2.0, YAML), Healthchecks.io (BSD, also self-hostable), OneUptime (Apache 2.0), Nagios Core (GPLv2), Zabbix (AGPL). Skipped: anything Business-Source-Licence — see methodology.** ## The ranking - Uptime Kuma — MIT-licensed, one-command Docker install, sane dashboard - SigNoz — Open-source Datadog alternative — MIT, OTel-native - Gatus — YAML-config-as-code uptime monitoring, Apache 2.0 - Healthchecks.io — BSD-2-licensed cron + heartbeat monitoring, also self-hostable - OneUptime — Apache 2.0 all-in-one — uptime, status pages, incident management - Nagios Core — GPLv2 — the original open-source monitoring tool - Zabbix — AGPL — full-fat infra + web monitoring ## OSI-approved licences only — why we drew the line there The phrase "open source" has been heavily diluted since 2018, when companies like Elastic and HashiCorp moved popular projects onto Business Source Licence and SSPL. Those licences read like open source but legally aren't — you can read the code, but you can't compete with the vendor that publishes it. We exclude them from this list. Every tool below ships under an OSI-approved licence: MIT, Apache 2.0, BSD-2, GPLv2, or AGPL. If your reason for picking open source is procurement compliance or fork-ability, that distinction matters; if it's just "I want it free", see the free-website-monitoring ranking instead. Of the seven projects that survive the licence test, Uptime Kuma is the one we recommend by default. The licence is real (MIT), the install is one Docker command, the dashboard is the cleanest in the category, and the project ships releases monthly. SigNoz is a different category answer — it's an open-source Datadog replacement, OpenTelemetry-native, MIT-licensed, and meaningful at scale. Gatus is the answer for teams whose monitoring config lives in Git alongside everything else; YAML in, alerts out, no UI required. The downside of every entry on this list is the same: someone has to run it. The hidden cost of self-hosted monitoring is the second monitor — the one watching the monitor. Uptime Kuma running on the same VPS as the website it monitors is a one-failure-mode setup. Plan for an external probe (a $7/mo UptimeRobot account or a free Healthchecks.io ping) so you find out when your self-hosted monitor itself goes down. ### What is the best open-source website monitoring tool in 2026? As of May 2026, Uptime Kuma is the best open-source website monitoring tool for most teams — it's MIT-licensed, installs in one Docker command, ships monthly releases, and the dashboard is the cleanest in the category. For teams that want full observability (logs, metrics, traces) alongside uptime, SigNoz is the MIT-licensed Datadog alternative. For GitOps shops that prefer YAML config over a UI, Gatus (Apache 2.0) is the right choice. All three are OSI-approved licences — not Business Source Licence or SSPL. ### What does self-hosting open-source monitoring actually cost? The licence is free; the operational cost is not. In May 2026 we ran Uptime Kuma on a $6/mo Hetzner CX11 and Gatus on a $1.94/mo Fly.io Nano VM — total infrastructure under $10/mo. SigNoz is heavier: a 3-node Kubernetes cluster on DigitalOcean comes to roughly $60/mo. The hidden cost is the second monitor — you need an external probe to alert when the self-hosted monitor itself goes down. Budget a $7/mo UptimeRobot or free Healthchecks.io ping for that. ## Frequently asked questions ### What is the best open-source website monitoring tool in 2026? Uptime Kuma (MIT) for most teams — one Docker command, clean dashboard, monthly releases. SigNoz (MIT) if you want full observability. Gatus (Apache 2.0) if you keep config in Git. ### Is Grafana open source? Grafana itself is AGPL, which is OSI-approved. Some Grafana Enterprise features are not. Grafana's synthetic monitoring sits inside Grafana Cloud — see the cloud listing in our website-monitoring pillar. ### Why did you exclude Elastic and similar BSL-licensed tools? Business Source Licence and SSPL are not OSI-approved. They look like open source but restrict competing commercial use. We define open source by the OSI list; if you're flexible on that, the picture changes. ### Can I self-host monitoring on the same server as my website? Technically yes, practically no. If the server fails, both fail and no alert reaches you. Always run the monitor on separate infrastructure — or pair a self-hosted tool with a free external probe. ### Does Lemwatch have an open-source version? No. Lemwatch is closed-source SaaS. We include open-source tools in our rankings because they're often the right answer; we don't pretend to be one of them. Scoring rubric and test environments: [our methodology](https://lemwatch.com/best/methodology). ## Related - [All best-of guides](https://lemwatch.com/best) - [Best website monitoring](https://lemwatch.com/best/website-monitoring) - [Best self hosted website monitoring](https://lemwatch.com/best/self-hosted-website-monitoring) - [Best free website monitoring](https://lemwatch.com/best/free-website-monitoring) - [How we test](https://lemwatch.com/best/methodology) - [Lemwatch pricing](https://lemwatch.com/pricing) - [All monitoring checks](https://lemwatch.com/features)