Ensuring your website is always online is critical, but you don't need a huge budget to do it. There are fantastic free and open-source tools that provide reliable uptime monitoring. Here are 7 of the best options for 2025.

1. Uptime Kuma

The undisputed champion of open-source monitoring. Uptime Kuma is a self-hosted solution you can run on your own server, giving you complete control over your data. It features a beautiful, modern interface, supports a wide range of monitor types (HTTP, DNS, Ping, etc.), and allows for unlimited monitors. For those who want power and privacy without cost, this is the top choice.

2. RobotAlp

RobotAlp offers a feature-rich and incredibly generous free uptime monitoring plan. As a SaaS platform, it requires no setup on your end. The free tier includes 20 monitors with 3-minute check intervals and access to 14 different monitoring tools (like SSL, PageSpeed, and Blacklist monitoring), making it one of the most comprehensive free offerings available.

3. UptimeRobot

One of the most popular and long-standing names in the industry, UptimeRobot’s free plan is a solid choice for beginners. It includes 50 monitors with 5-minute check intervals and basic status pages. It's a reliable and straightforward service to get you started with monitoring.

4. Freshping

From the makers of Freshdesk, Freshping offers a very generous free plan. You get 50 monitors with 1-minute check intervals from 10 global locations. The plan also includes SSL monitoring and support for multiple users, making it a powerful free option for small teams.

5. Gatus

An innovative open-source health dashboard that is perfect for a more technical audience. Instead of just checking if a site is "up" or "down," Gatus allows you to define complex conditions for what "healthy" means (e.g., "HTTP status is 200 AND latency is under 300ms"). It’s configured via YAML and provides a clean, simple dashboard.

6. Checkmk (Raw Edition)

For those who need to monitor more than just websites, Checkmk is an enterprise-grade, open-source infrastructure monitoring tool. The free "Raw Edition" is incredibly powerful, allowing you to monitor the health of your servers, network, and applications. While it has a steeper learning curve, its capabilities are immense.

7. Zabbix

Another powerhouse in the open-source world, Zabbix is a comprehensive, enterprise-level monitoring solution. It can monitor virtually anything in your IT infrastructure, from server performance and network devices to web applications. It's a highly flexible and scalable solution for users who need deep, all-encompassing monitoring capabilities.

7 Best Free Uptime Monitoring Tools for 2025