GTM & Facebook Purchase tag: event_id is not being recognised in FB Event Manager

Question

We use client-side GTM (cGTM) for the Facebook tags and we also have server side GTM (sGTM) for Facebook conversion api.

We noticed that in Facebook Event Manager in "Test your events" section the Event ID is not being recognised although we do send it. Below in the screenshoot I overexaggerated an example with different writings/property names of event id as I was not sure why in Facebook they are not mapped to Event ID column.

This is important for the deduplication of events that are coming from server (FB CAPI via sGTM) and browser side (pixel via cGTM FB tag). On the sGTM aka server we have event_id in payload and the Event Id column is filled.

But I don't understand why Event ID column in Browser is not filled given we do send event ids. What should be the spelling of event if in cGTM in Facebook Tag for FB to map it?

Answer 1

"eventID" is the correct property name.

But if the event you are sharing does not contain parameters such as value and currency, you can set it up as follows:

fbq('track', 'Lead', {}, {eventID: '123'});

I guess you deleted the the empty {}, that's why your eventID is not recognized.