Free Uptime Monitor for Cloudflare Workers

A free, open-source uptime monitoring tool that runs entirely on Cloudflare Workers. It auto-discovers all domains on your Cloudflare account and monitors them, with alerts via Telegram and email.

Zero cost — runs within Cloudflare's free tier (supports up to ~200 monitors).

• Auto-discovery — automatically monitors every active domain in your Cloudflare account
• Manual monitors — add any URL through the dashboard
• 5-minute checks — HTTP health checks with response time tracking
• 1-minute re-checks — down sites are re-checked every minute for faster detection
• Password-protected dashboard — dark-themed UI with uptime bars, response time charts, and incident history
• Telegram alerts — instant notifications when a site goes down or recovers
• Email alerts — via Resend API
• Smart alerting — requires 2 consecutive failures before alerting (no false positives, ~1 min detection)
• Incident tracking — logs downtime periods with duration
• Edit, pause, delete — full control over each monitor from the dashboard
• Down-first sorting — down monitors always appear at the top
• 7-day retention — automatic cleanup of old data

• A Cloudflare account (free)
• Node.js 18+
• A Telegram bot and chat/group ID
• A Resend account (free tier: 100 emails/day)

git clone https://github.com/estevecastells/uptime-monitoring-workers.git
cd uptime-monitoring-workers
cp wrangler.toml.example wrangler.toml
npm install

npx wrangler d1 create uptime-monitor-db

Copy the database_id from the output and paste it into your wrangler.toml:

[[d1_databases]]
binding = "DB"
database_name = "uptime-monitor-db"
database_id = "your-database-id-here"  # <-- paste here

npx wrangler d1 migrations apply uptime-monitor-db --remote

npx wrangler secret put CLOUDFLARE_API_KEY     # Your CF Global API key
npx wrangler secret put CLOUDFLARE_EMAIL       # Your CF account email
npx wrangler secret put TELEGRAM               # Format: BOT_TOKEN|CHAT_ID
npx wrangler secret put RESEND                 # Your Resend API key
npx wrangler secret put ALERT_EMAIL            # Email address to receive alerts
npx wrangler secret put DASHBOARD_PASSWORD     # Password to access the dashboard

1. Create a bot with @BotFather → you'll get a bot token like 123456789:AAGxyz...
2. Add the bot to a group, or message it directly
3. Get your chat ID by messaging @userinfobot on Telegram, or check https://api.telegram.org/bot<YOUR_TOKEN>/getUpdates after sending the bot a message
4. Set the secret as BOT_TOKEN|CHAT_ID (pipe-separated). Example: 123456789:AAGxyz...|-1001234567890

On the free tier without a verified domain, Resend only delivers to the email address you signed up with. To send to any address, verify a domain in your Resend dashboard and add the required DNS records.

npx wrangler deploy

Your monitor is now live at https://uptime-monitor.<your-subdomain>.workers.dev

The dashboard is protected by a password (the DASHBOARD_PASSWORD secret). When you visit the URL, you'll see a login screen. Sessions last 30 days.

For additional security, you can also put Cloudflare Access (free) in front of it:

1. Go to Cloudflare Zero Trust
2. Access > Applications > Add an application
3. Choose Self-hosted, enter your worker URL
4. Create a policy (e.g., allow your email address)

Create a .dev.vars file with your secrets (never commit this):

CLOUDFLARE_API_KEY=your-api-key
CLOUDFLARE_EMAIL=your@email.com
TELEGRAM=bot-token|chat-id
RESEND=re_your-resend-key
ALERT_EMAIL=your@email.com
DASHBOARD_PASSWORD=your-password

Then run:

npx wrangler d1 migrations apply uptime-monitor-db --local
npx wrangler dev --test-scheduled

Visit http://localhost:8787 to see the dashboard.

1. Every 5 minutes, all active monitors are checked
2. If a site is down, it's re-checked every minute
3. After 2 consecutive failures (~1 minute apart), a DOWN alert is sent via Telegram and email
4. When the site recovers, a RECOVERED alert is sent
5. No duplicate alerts — each downtime period is tracked as an incident

• Runtime: Cloudflare Workers (free tier)
• Database: Cloudflare D1 (SQLite)
• Router: Hono
• UI: Server-rendered HTML (no build step, no frontend framework)
• Notifications: Telegram Bot API + Resend email API

Comfortably supports up to ~200 monitors on the free tier.

Run the test suite before submitting a PR:

npm test

Tests use Vitest with Cloudflare's Workers test pool, so they run against a real D1 database in a local Workers runtime. The suite covers:

• DB queries — CRUD operations, soft-delete, stats, cleanup
• Health checker — check logic, incident creation after 2 failures, recovery
• API routes — auth, monitor CRUD, toggle, validation
• Notifications — Telegram and email payload formatting
• Zone discovery — sync, deactivation, soft-delete protection

Contributions are welcome! Feel free to open issues, submit pull requests, or fork the project for your own use. Whether it's bug fixes, new features, documentation improvements, or ideas — all contributions are appreciated.

Please run npm test and make sure all tests pass before submitting a PR.

MIT — free and open source. Use it however you want, including commercially. Fork it, modify it, sell it, deploy it for your clients — no restrictions beyond the MIT license terms.