🟢 DELIVERED - Custom Experiment exposure events

Thanks for this idea @lance I’ve shared it with our product team for review!

@lance looks like the support team got back to you with an answer (and a few questions to help dig into this further if you’d like).

Posting the answer here to help another member with the same question:

When it comes to Experiment, we usually strongly recommend automatic exposure tracking. The reason for this is that the automatic exposure events triggered by our SDK do not count toward your monthly event limit. If you were to instrument it incorrectly and send a load of Experiment exposure and assignment events, they would not count towards your monthly limit. If you were to instrument it incorrectly on a custom exposure event, each custom exposure event would count towards your traffic, while automatic exposure tracking is "free". Automatic exposure tracking is less susceptible to instrumentation issues. It is also easier to implement than a custom exposure event.
 
We recommend the custom exposure tracking if you truly want to implement your own exposure event. However, we only recommend this if you are very comfortable with Experiment and know what you are doing. We do recommend testing custom exposure tracking in a dummy project before implementing it in production, if you were to choose to do so. It can also be that a user may be assigned but never fire the exposure event if there is an issue and this could cause further analysis issues. 
 
With regards to the custom exposure event, this would be the exposure event itself, in place of the Amplitude exposure event. So I do not believe we have the ability to be able to change this but you are always free to change it back to the recommended exposure.

hey folks! Thanks for getting back to me. I’ve responded to the email but i’ll also place my response here for other members -- this is mainly to provide more context around this request.

We'll typically use a custom exposure event when we already have an existing event instrumented that happens to also indicate exposure. For example, we have some existing events that track a view on a particular module that could be further down on a given page and we might run an experiment to test different versions of that module. The client will render that module regardless of whether the user scrolls down to view it or not, but we only want to consider the user exposed if they actually scrolled down and had it in view -- in this case we'd use the module viewed event as a custom exposure event. In this case, we wouldn't be impacting our monthly limit since the event already exists. 

I mainly ask if it's possible to trigger an `[Experiment] Exposure` event in this case because we utilize the exposure data to analyze metrics between our variants outside of amplitude. Having the '[Experiment] Exposure' passed allows us to easily determine the user's variant in the event streaming data that we export, but in this case we could just use the module viewed event so no worries!

Thanks for your feedback, ​@lance! I’m going to close out this post since this feature is delivered.