As you know, we are dedicated to providing a simple, no-cost uptime monitoring service. Because we are a completely free service with no revenue model, we can only serve a very limited number of users.
The 7 Best Free Uptime Monitoring Tools (2025 Guide)
Hello from the team at freeuptime.org! As you know, we are dedicated to providing a simple, no-cost uptime monitoring service. Because we are a completely free service with no revenue model, we can only serve a very limited number of users. We are proud to have been providing our service for a year now and want to emphasize that we will continue to offer it for free in the coming year.
Of course, while we provide a limited service (just one location and 5-minute pings), we recognize that there are better, more comprehensive free uptime monitoring tools available worldwide. That's why I wanted to share a personal list of tools that I have either used myself or received support from in the past. While you can find a more extensive list of options in this great blog post about Free Website Monitoring, the 2025 list below is a shorter, curated selection of 7 tools that I can confidently recommend based on my own experience.
Here are my top picks for the best free and open-source uptime monitoring tools for 2025:
- RobotAlp
RobotAlp takes the top spot due to its incredible balance of user-friendliness and comprehensive features, especially in its free offering. It’s designed as an all-in-one monitoring solution that allows you to get a holistic view of your website's health, not just its availability. The dashboard is clean and intuitive, making it easy for anyone to set up complex checks without a steep learning curve. It's a professional-grade service that offers immense value right out of the box.
- Advantages:
- Generous Free Plan: Get access to 14 different monitoring tools, completely free.
- High Monitor Count: Set up to 20 monitors to cover all your critical services.
- Frequent Checks: A 3-minute ping interval ensures you're notified of issues quickly.
- Global Perspective: Check your website's status from 9 different locations around the world.
- Public Status Pages: Easily create status pages to keep your users informed.
2. Uptime Kuma
A true star of the open-source community, Uptime Kuma is a beautifully designed, self-hostable monitoring tool. By running it on your own server, you gain complete control and privacy over your monitoring data. Its modern interface is a pleasure to use, and its active development ensures it stays up-to-date with the latest needs of developers and system administrators.
- Advantages:
- Completely Free & Self-Hosted: No subscription fees and full data ownership.
- Unlimited Monitors: Track as many services as your server can handle.
- Wide Protocol Support: Monitors HTTP(S), TCP, Ping, DNS records, and more.
- Stylish Status Pages: Create beautiful, customizable status pages for your services.
3. freeuptime.org
Sometimes, simplicity is the ultimate feature. freeuptime.org embodies this philosophy perfectly. It's a no-frills, web-based tool designed to do one thing and do it well: check if your website is up. There are no complex dashboards or configurations to worry about, making it an excellent choice for users who need a quick and easy way to set up a basic uptime check.
- Advantages:
- Extremely Simple: The most straightforward tool on this list.
- No Setup Required: Just enter your URL to get started.
- Completely Free: No hidden costs or premium tiers.
- Purpose-Driven: Ideal for basic ping checks without extra complexity.
4. Prometheus & Grafana
For technical teams that crave data and deep customization, the combination of Prometheus and Grafana is unbeatable. Prometheus is a powerful open-source time-series database and monitoring system that excels at collecting metrics from any source. For uptime, it's often paired with the "Blackbox Exporter." Grafana then steps in to transform that raw data into stunning, insightful, and fully interactive dashboards.
- Advantages:
- Unmatched Customizability: Build dashboards that show exactly the data you need.
- Powerful Alerting: Create complex alert rules based on your metrics.
- Cloud-Native Standard: The go-to solution for monitoring Kubernetes and modern infrastructure.
- Massive Ecosystem: A huge community and extensive documentation are available.
5. Nagios Core
Nagios Core is a true industry veteran and one of the most powerful open-source monitoring frameworks available. It’s known for its rock-solid stability and incredible flexibility. While its configuration can be more hands-on, it gives you granular control over every aspect of the monitoring process, from check logic to complex notification and escalation chains.
- Advantages:
- Highly Extensible: Thousands of community-written plugins allow you to monitor virtually anything.
- Powerful Event Handling: Advanced logic for how and when to send notifications.
- Proven Reliability: Battle-tested over many years in enterprise environments.
- Strong Community Support: A large community provides support and resources.
6. Zabbix
Zabbix offers a complete, enterprise-grade monitoring experience in a single open-source package. It’s designed to be an all-in-one solution, capable of monitoring servers, networks, applications, and cloud services without needing multiple different tools. Its powerful templating system and auto-discovery features make managing large and dynamic environments much simpler.
- Advantages:
- All-in-One Solution: Covers a vast range of monitoring needs in one platform.
- Auto-Discovery: Automatically finds and starts monitoring new devices on your network.
- Flexible Templating: Easily apply monitoring configurations to many hosts at once.
- Completely Free Core: The full-featured software is free to use without limitations.
7. Gatus
Gatus is a modern, developer-friendly, open-source health dashboard tool with a unique approach. Instead of just a binary up/down status, it evaluates the health of your services based on a set of conditions you define. This allows for more intelligent and meaningful alerting, ensuring you're only notified when multiple criteria for failure are met.
- Advantages:
- Condition-Based Alerting: Create smart alerts (e.g., status == 200 AND response_time_ms < 500).
- Configuration as Code: The entire setup is managed through a simple YAML file, perfect for GitOps workflows.
- Clean & Simple Dashboard: Provides an at-a-glance overview of your services' health.
- Lightweight & Stateless: Easy to deploy and manage.
A Quick Guide: How to Find the Correct Free & Open-Source Versions
The world of open-source can sometimes be confusing, as popular projects often have commercial companies offering paid services or enterprise versions alongside the free, community-driven software. This doesn't mean the core tool isn't free; it just means you need to know where to look. Here’s a quick guide on how to access the correct free and open-source editions for the tools we've mentioned:
- For Prometheus & Grafana:
- Prometheus is a fully open-source project managed by the CNCF. You can always find the latest free version to download directly from its official website, prometheus.io. There is no paid version of Prometheus itself.
- For Grafana, the key is to look for "Grafana OSS" (Open Source Software). When you visit the Grafana website, you will see options for a paid "Grafana Cloud" and "Grafana Enterprise." You should navigate to the "Download" or "Self-managed" section, where you will find the free, open-source version that you can install and run on your own servers without any cost.
- For Nagios Core:
- It is vital to distinguish between Nagios Core and Nagios XI. Nagios Core is the powerful, free, and open-source monitoring engine that forms the heart of the project. This is the version you want, and you can download it from the official Nagios projects website (nagios.org). Nagios XI is the paid commercial product sold by Nagios Enterprises, which includes a pre-packaged web interface and additional features on top of the Core engine.
- For Gatus:
- Gatus is the most straightforward case. It is a purely community-driven, open-source project without any commercial version or company behind it. You can find its code, installation instructions, and releases directly on its GitHub repository (github.com/TwiN/gatus).
By looking for the "Core," "OSS," "Community Edition," or "Self-hosted" options, you can confidently leverage the immense power of these fantastic monitoring tools entirely for free.