Webhooks in Mailchimp API work perfectly fine most of the times but there is a small catch. If you import a bunch of subscribers to your list by importing a CSV file (or copy/paste etc.), then any webhooks registered on that particular list don’t fire.
But there is a workaround. You need to do the following:
- Create a new temporary list.
- Import your CSV file into that list.
- Then select the imported contacts on Mailchimp UI and move them into actual list on which you have registered webhooks.
- At that point, Mailchimp will dispatch any necessary webhooks for the contacts you have imported.
Did you ever run into this problem? If so, please give the above mentioned steps a go and let me know in comments if it worked for you or not.
Credit
I got this solution from here: https://www.sugaroutfitters.com/support/SugarChimp/1311