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Mailchimp Integration - Prohibiting More Than One Submission

Hi all -

We are using the Mailchimp integration to post form submissions for a sweepstakes registration. It’s limited to one per person/email. Has anyone found a way to prohibit posts from being submitted if one has already been submitted?

Alternatively, if there is no solution, any ideas on:

  • Prompting an error message if same email has already been submitted

  • Storing form results in parallel within Webflow and using webflow for this control to prohibit the post from going through to Mailchimp if it’s already been submitted

Read-Only Link is:

Published link is:

Any creative ideas?


Would a potential solution be to do this?

  1. Prior to “post”, search for email address in CMS collection
    2a. If email does not exist, add it and then “post”
    2b. If email does exist, alert that only one registration allowed, and do NOT “post”


Shouldn’t MailChimp already handle duplicate emails?

Hi @samliew! Thanks for the feedback. Yes, Mailchimp should. In fact, they do to some extent. They actually don’t allow a duplicate, and therefore subsequent registrations won’t be accepted/loaded. But the user experience is flawed, because there is no message thrown when a duplicate is attempted. This is the issue we’re hoping to solve for.


I wonder if anyone has come up with a solution to this since last August… :slight_smile:

The issue: When a user attempts to submit a form integrated with MailChimp using the same email address which already exists in the mailing list, the attempt fails in Webflow, based on the error message returned by MailChimp.

Is there any way to solve this – even if just by letting the user know about the cause (i.e., multiple signup attempt)?

The MailChimp error (visible in the browser console) also provides a link offering to edit the user’s preferences in the MailChimp account. Is there any way to provide this link within the Webflow form?

Thank you!

Hi, I am having the same problem with our page right now. Any chance you have come up with a solution for this? I am thinking to user Zapier as a middleman to avoid the error message in the form itself.

Hi @bueromarco

There is a new Webflow video about MailChimp integration. Here is the link, see if it helps with your case?

Best Regards,
~ Brandon

Hi @WebDev_Brandon , thanks for the heads-up. Unfortunately the video doesn’t cover what should be done when a user signs up to a mailchimp list which already holds his email adress. I have set up the system with Zapier which solves the problem of the Webflow form showing an error code when the user already exists in the Mailchimp list. Would be great if the form could handle that situation natively though.

Hi @bueromarco,

When you use Zapier, you can set up the connection to update/create a new field. So if the email already exists, it will overwrite or just ignore it.

As for natively built-in with Webflow, we know and understand this is a pain point for our users and are looking into more ways that our forms can offer these solutions without using a service like Webflow. However, I do not have a finished timeline for such a feature.

Best Regards,
~ Brandon