Mailchimp unset a merge var via api

Question

I have a working sync between my local DB and mail chimp. In most cases it works fine. However there is one case that doesn't seem to work.

I am updating subscribers using the Subscribe method. With both update_existing and replace_interests set to true.

I can set merge vars via this method. However I don't seem to be able to unset them.

I have tried

• Not putting item in the array at all.
• Passing an empty string in the merge vars array for the value.
• Passing flase as the value.
• Passing null as the value.

None of which seem to affect the value at all.

Answer 1

Although this question is quite dated, I've found that passing an empty string does in fact unset a merge field.

Using the Mailchimp API to edit a list member via PUT or PATCH:

{ 'FNAME': 'John', 'LNAME: '' }

The above will unset any previously set LNAME.