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Health Checks

Monitor the availability of your web services.

Health checks are currently available only for web services.

You can (and should!) define a health check endpoint for every web service to help Render determine whether it’s ready to receive traffic. Render sends an HTTP request to this endpoint as part of zero-downtime deploys, and also every few seconds to verify the health of running services.

Set your health check endpoint path in the Render Dashboard from your web service’s Settings page:

Setting health check path in the Render Dashboard

If you manage your service with a Blueprint, instead set the healthCheckPath field in your render.yaml file.

Health check protocol

With every health check, Render sends an HTTP GET request to each service instance’s health check endpoint. If your service has at least one custom domain, Render sets one of those domains as the value of the Host header for the request. Otherwise, Render uses the service’s onrender.com subdomain.

  • The check succeeds if your health check endpoint responds with a 2xx or 3xx status code. Render considers the instance healthy.
  • The check fails in all other cases (including after a 5-second response timeout). Render considers the instance potentially unhealthy.

If a potentially unhealthy instance continues to fail its health checks, Render takes the following actions:

  • During a zero-downtime deploy:
    • If a new instance fails all of its health checks for 15 consecutive minutes, Render cancels the deploy and continues routing traffic to existing instances.
  • For an actively running service:
    • If an instance fails all of its health checks for 15 consecutive seconds, Render stops routing traffic to it to give it an opportunity to recover.
    • After 60 consecutive seconds of failed health checks, Render automatically restarts the service.

In the event of a canceled deploy or a service restart, Render notifies you according to your settings.

The actions your endpoint should take to verify service health depend on your service’s details.

We recommend performing operation-critical checks, such as executing a simple database query to confirm connectivity.