and on server side, we don't send anything other than what you define on the trackingCallback

for the HTML snippet we do the experiment_viewed event automatically -but you can override that if you want

However we just use the default snippet, nothing else.

@fresh-football-47124 when exactly does the experiment_viewed event trigger? It might help us get to the cause of the issue.

Do I understand well, i looked into trackingCallback and it seems to be only needed in custom implementations? if we have the standard snippet + GA4 event installed via GTM we don't need to do anything? I can't find the right docs.

We fire one event when a user sees an experiment

which is fired from the trackingCallback, and fires an event called 'experiment_viewed'

if you're adding the HTML SDK, we fire that event automatically, but you can override it