Oh Dear + Alert24 Healthcheck Integration

Oh Dear is a developer-focused monitoring service that checks sites from multiple locations and verifies from a secondary location before alerting. It evaluates 2xx responses as healthy, making it compatible with Alert24 healthcheck endpoints without any additional configuration.

Before you start

You'll need:

• An Alert24 API key (Settings → API Keys → Create API Key)
• The ID of the check you want to monitor, found in Monitoring → [check name] or via the API

Add a monitor

1. In Oh Dear, click Add a new site
2. Paste your healthcheck URL:

   https://app.alert24.net/api/healthcheck/ak_live_YOUR_KEY/YOUR_CHECK_ID
   

3. Give it a friendly name (e.g. "Payment Gateway — Alert24")
4. Under Checks, enable Uptime and performance monitoring
5. Set your preferred check frequency (every minute is the default)
6. Configure notification channels
7. Click Save

Oh Dear checks from a primary location every minute and verifies failures from a secondary location before sending notifications, which prevents false alerts from transient network issues.

Org-wide monitor

To create a single monitor that covers all your active Alert24 checks:

https://app.alert24.net/api/healthcheck/ak_live_YOUR_KEY

Tips

• Multi-location verification: Oh Dear's primary-plus-secondary check model complements Alert24's multi-location check infrastructure. A real outage will be caught by both systems; a transient connectivity blip between Oh Dear and Cloudflare's edge won't trigger an alert.
• Cache-Control header: Alert24 sends Cache-Control: no-store on all healthcheck responses. Oh Dear respects this and will never serve a cached result.
• $OH_DEAR_TIMESTAMP variable: Oh Dear supports cache-busting URL variables. You can append ?ts=$OH_DEAR_TIMESTAMP to the healthcheck URL if you want to guarantee no CDN caching (though Cache-Control: no-store already handles this).
• Performance metrics: Oh Dear records TCP connection time, TLS handshake time, and server response time. Since the healthcheck endpoints are served from Cloudflare's edge, you'll see consistently low server response times — useful as a baseline.