What is Heartbeat?
Learn what the Crash Shield heartbeat endpoint does and how it is separated from the frontend probe.
What is Heartbeat?
Heartbeat is the GET /wp-json/anchoruptime/v1/heartbeat endpoint that the WordPress plugin opens. Anchor Uptime calls this address in the control loop and expects a status=ok response.
Probe
Signal
If there is an active PHP error, the endpoint returns status=error; otherwise it returns status=ok. This generates a signal specific to the WordPress layer.
Difference from Frontend Probe
| Frontend Probe | Heartbeat | |
|---|---|---|
| Source | Anchor Uptime servers call the URL from outside. | Anchor Uptime servers call the WordPress heartbeat endpoint. |
| Target | The page open to the user or the URL you provide. | /wp-json/anchoruptime/v1/heartbeat |
| Measured by | HTTP availability and response time. | Whether the WordPress/PHP layer is responsive and has an active fatal. |
| Do you need WordPress? | No. | Yes |
| Will it catch the silent fault? | Not always | Yes, especially useful in fatal/cached page parses |
Silent Failure Scenario
Example: The CDN or full-page cache may still be returning 200 for the main URL, but a new fatal error may have been activated within WordPress. In this case, the heartbeat endpoint responds error while the frontend probe up appears.
The decision engine marks this combination as degraded. This means that you may notice degradation in the application layer before the site appears completely down.
Is it mandatory?
Heartbeat is optional.
Frontend uptime monitoring continues without the plugin installed. With Heartbeat added, you only gain a second signal; you can more clearly distinguish internal error scenarios, especially WordPress-based ones.