Notification listeners

Notification listeners:

Give you flexibility in implementing custom integrations with analytics providers.
Enable integrations by passing data to external services.

Here are a few examples for using notification listeners:

Send data to an analytics service and report feature flag decision data, for example, report that user_123 was assigned to variation A.
Use SDK events to send alerts to data monitoring tools like New Relic and Datadog to visualize better how A/B tests affect service-level metrics.
Pass all events to an external data tier, like a data warehouse, for additional processing and to leverage business intelligence tools.
Re-initialize your SDK to quickly retrieve updated feature flag configuration data for your business-critical features.

The listeners work by triggering a callback function that you define and provide at runtime.

The following methods or lifecycle events trigger notification listeners if you have implemented the listener:

For notification listeners triggered by older methods such as Is Feature Enabled and Activate, see the Full Stack (Legacy) version of this page.

Method	Notification listener invoked
Decide methods	Invoke the DECISION notification listener if this listener is enabled.
Track Event	Invokes the TRACK notification listener if this listener is enabled. Important! This method will not call the TRACK notification listener when the specified event key is invalid

SDK Lifecycle event	Notification listener invoked
event batch flushed	Invokes the LOGEVENT notification listener if this listener is enabled
new datafile retrieved	Invokes the OPTIMIZELYCONFIGUPDATE notification listener if this listener is enabled.

For more information about each listener type, see: