Some example plugins that can be used as a starting point for custom development:

• routing rules plugin that uses different notification paths for different customers. ie. PagerDuty for Tier 1 customers, Slack for Tier 2 and nothing for Tier 3 customers.

• transient alert plugin based on the is_flapping() helper method will reject alerts that have repeatedly changed from an alert severity to normal within a short period of time. eg. more than twice in 2 minutes

See the alerta contrib repo for a comprehensive list of plugins that can be used as-is or as examples for your own environment.