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Event delivery


When you receive an event, acknowledge the delivery by returning an HTTP 200 or 202 status code. Anything 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 Optimizely Content Marketing Platform 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.

If you make multiple identical requests and receive the same response every time, the APIs are generally called idempotent. Some API consumers knowingly or unknowingly make the same request twice or thrice. The APIs have to understand this and reply with the same response.


If delivery fails, CMP retries to deliver the event for up to three days with an exponential back off.


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.