Custom metrics refers to any metrics that are not part of the regular integration suite, for example using custom checks or API-level metrics in your application stack. Some standard integrations can potentially emit custom metrics.
Pro plans include 100 custom metrics per host and Enterprise plans include 200 custom metrics per host. This number is averaged across all paid hosts. Additional custom metrics packages can be purchased.
For technical questions, contact Datadog support.
For billing questions, contact your Customer Success Manager.