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Checkmate

An open source uptime and infrastructure monitoring application

This repository contains both the frontend and the backend of Checkmate, an open-source, self-hosted monitoring tool for tracking server hardware, uptime, response times, and incidents in real-time with beautiful visualizations. Checkmate regularly checks whether a server/website is accessible and performs optimally, providing real-time alerts and reports on the monitored services' availability, downtime, and response time.

Checkmate also has an agent, called Capture, to retrieve data from remote servers. While Capture is not required to run Checkmate, it provides additional insights about your servers' CPU, RAM, disk, and temperature status. Capture can run on Linux, Windows, Mac, Raspberry Pi, or any device that can run Go.

Checkmate has been stress-tested with 1000+ active monitors without any particular issues or performance bottlenecks.

📚 Table of contents

• 📦 Demo
• 🔗 User's guide
• 🛠️ Installation
• 🚀 Performance
• 💚 Questions & Ideas
• 🧩 Features
• 🏗️ Screenshots
• 🏗️ Tech stack
• 🔗 A few links
• 🤝 Contributing

Demo

You can see the latest build of Checkmate in action.

The username is demouser@demo.com and the password is Demouser1! (just a note that we update the demo server from time to time, so if it doesn't work for you, please ping us on the Discussions channel).

User's guide

Usage instructions can be found here.

Prerequisites

• Docker installed
• Git installed

Installation

The quickest way to run Checkmate is the reference Docker Compose file, which runs the all-in-one image (ghcr.io/bluewave-labs/checkmate) plus MongoDB:

curl -O https://raw.githubusercontent.com/bluewave-labs/checkmate/master/docker/docker-compose.yaml
JWT_SECRET="$(openssl rand -hex 32)" docker compose up -d

Then open http://localhost:52345. If the app is reached at another origin (domain or LAN IP), set CLIENT_HOST accordingly. To build the image yourself, run docker build -f docker/Dockerfile -t checkmate . from a checkout. For TLS, put any reverse proxy (Caddy, Traefik, nginx) in front of port 52345.

Configuration

The image is configured entirely through environment variables on the server container:

Variable	Required	Description
DB_CONNECTION_STRING	Yes	MongoDB connection string, e.g. mongodb://mongodb:27017/uptime_db
JWT_SECRET	Yes	Secret used to sign auth tokens; generate one with openssl rand -hex 32
CLIENT_HOST	Yes	The URL users reach the app at, e.g. https://checkmate.example.com; used for CORS and for links in notifications and emails
LOG_LEVEL	No	Server log level: error, warn, info, or debug (default debug)

The web client needs no configuration by default: it calls the API on the same origin it was served from (/api/v1). For setups where the defaults don't apply — for example, the API is reached through a different origin than the page — the server renders overrides into the client at runtime via these optional variables:

Variable	Description
CLIENT_CONFIG_API_BASE_URL	Full base URL the client calls the API at, e.g. https://api.example.com/api/v1; defaults to same-origin /api/v1
CLIENT_CONFIG_CLIENT_HOST	Origin used when the client builds absolute links (invites, status pages); defaults to the browser's current origin
CLIENT_CONFIG_LOG_LEVEL	Browser console log level: error, warn, info, or debug (default error)

Upgrading from an older image? The UPTIME_APP_* variables (UPTIME_APP_API_BASE_URL, UPTIME_APP_CLIENT_HOST, UPTIME_APP_LOG_LEVEL) are no longer read. In most setups no replacement is needed — the same-origin defaults cover them; if you pointed the client at a different origin, use the CLIENT_CONFIG_* equivalents above. The checkmate-client, checkmate-backend, checkmate-mongo, and checkmate-backend-mono-multiarch images are no longer updated — switch to ghcr.io/bluewave-labs/checkmate, keeping your existing MongoDB service and data volume.

See full installation instructions in the Checkmate documentation portal.

Alternatively, you can also use Coolify, Elestio, K8s, Sive Host (South Africa), Cloudzy or Pikapods to quickly spin off a Checkmate instance. If you would like to monitor your server infrastructure, you'll need Capture agent. Capture repository also contains the installation instructions.

Using a Custom CA

If you need to monitor internal HTTPS endpoints with certificates from private Certificate Authorities (like Smallstep), see our Custom CA Trust Guide for Docker configuration options.

For more documentation, see the docs directory.

Performance

Thanks to extensive optimizations, Checkmate operates with an exceptionally small memory footprint, requiring minimal memory and CPU resources. Here’s the memory usage of a Node.js instance running on a server that monitors 323 servers every minute:

You can see the memory footprint of MongoDB and Redis on the same server (398Mb and 15Mb) for the same amount of servers:

Questions & Ideas

If you have any questions, suggestions or comments, you have several options:

• Discord channel (preferred)
• GitHub Discussions (we check here from time to time)

Feel free to ask questions or share your ideas - we'd love to hear from you!

Features

• Completely open source, deployable on your servers or home devices (e.g Raspberry Pi 4 or 5)
• Several monitoring options: Uptime, Docker, Ping, SSL, Port, Game server
• Page speed monitoring
• Infrastructure monitoring (memory, disk usage, CPU performance, network etc) - requires Capture agent
  • Selective disk monitoring with mountpoint selection
• Incidents at a glance
• Status pages with 4 beautiful themes
• E-mail, Webhooks, Discord, Slack, PagerDuty, Matrix, Microsoft Teams, Telegram, Pushover, Twilio (SMS) notifications
• Scheduled maintenance
• JSON query monitoring
• Multi-language support for Arabic, Chinese (Simplified), Chinese (Traditional, Taiwan), Czech, English, Finnish, French, German, Japanese, Portuguese (Brazil), Russian, Spanish, Thai, Turkish, Ukrainian, and Vietnamese

Monitor Lifecycle

1. A monitor executes a check (HTTP / ping / port / hardware via Capture agent)
2. The result is stored (success/failure + response time)
3. Recent check results are evaluated against the monitor's configured status change threshold
4. If the monitor's status change threshold is met and the current status is not equal to the previous status, the monitor's state changes (e.g. initializing, up, down, breached)
5. Upon a state change: an incident is either created or resolved, depending on the monitor's current status
6. Notifications are triggered based on configuration

Screenshots

Tech stack

• ReactJs
• MUI (React framework)
• Node.js
• MongoDB
• Recharts
• Lots of other open source components!

A few links

• If you would like to support us, please consider giving it a ⭐ and click on "watch".
• Have a question or suggestion for the roadmap/featureset? Check our Discord channel or Discussions forum.
• Need a ping when there's a new release? Use Newreleases, a free service to track releases.
• Watch a Checkmate installation and usage video

Contributing

We are Alex (team lead), Gorkem, Aryaman, Mert and Karen helping individuals and businesses monitor their infra and servers.

We pride ourselves on building strong connections with contributors at every level. Despite being a young project, Checkmate has already earned 7000+ stars and attracted 90+ contributors from around the globe.

Our repo is starred by employees from Google, Microsoft, Intel, Cisco, Tencent, Electronic Arts, ByteDance, JP Morgan Chase, Deloitte, Accenture, Foxconn, Broadcom, China Telecom, Barclays, Capgemini, Wipro, Cloudflare, Dassault Systèmes and NEC, so don’t hold back — jump in, contribute and learn with us!

Here's how you can contribute:

0. Star this repo :)
1. Check Contributor's guideline. First timers are encouraged to check good-first-issue tag.
2. Read a detailed structure of Checkmate if you would like to deep dive into the architecture.
3. Open an issue if you believe you've encountered a bug.
4. Check for good-first-issue's if you are a newcomer.
5. Make a pull request to add new features/make quality-of-life improvements/fix bugs.
6. Check out this interactive walkthrough of the Checkmate codebase on CodeCanvas here. To refine existing dataflow simulation or create new ones, follow the quick tutorial here.