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Event delivery


When you receive an event, acknowledge the delivery by returning an HTTP 200 or 202 status code. Any status other than 200 or 202 is considered a delivery failure.

Delivery sequence

Optimizely Content Marketing Platform (CMP) does not guarantee the delivery of events in the sequence in which they are generated. You can use the CMP Open API to fetch the latest data.

Duplicate events

In rare cases, callback endpoints might receive the same event more than once. Make your event processing idempotent to guard against duplicated events.


In case of delivery failure, Optimizely CMP tries to deliver the event again, for up to three days, with an exponential backoff.


It is expected that the callback endpoint will respond within 10 seconds of receiving the webhook event. If it takes more then 10 seconds, the connection is terminated and will be considered a delivery failure.