mailchimp trigger API automation for 'already subscribed'

Question

we use Mailchimp automation. For new clients that fill out our form this works fine - we send them a welcome e-mail and an offer.

The problem now occurs here: we have noticed that about 12-20% of already subscribed customers don't realize they are subscribed ---- and subscribe again!

However there is no API event that marks this event to our knowledge. We would ate least like to 'inform' the 'already subscribed' that they are already subscribed - or give them a small extra. But don't let it end in a dead track (no response at all).

So ideally we would like to

• (possible) new customers: send welcome and offer
• (not possible?) already subscribed: inform them + give small extra

my question is: how can we specifically target already subscribed customers that subscribe a second time (and exclude new subscribers) coming from the API through automation in Mailchimp?

Has anyone done something like this before? We use the Hellobar btw. We don't want people who fill out a form: to hear nothing from us.

UPDATE: As suggested by @TooMuchPete maybe through and API error. But there is no link to an 'error' trigger

Example op API 3.0 set-up

Answer 1

You could create a second Automation that is API triggered. Then, when your API subscribe call results in a 'user already subscribed' error, you could add them to that automation.