How to connect your campaign to Mailchimp

Connecting Mailchimp lets you sync subscribers from your 1ClickPopup campaigns directly to your Mailchimp audience – including custom fields, customer tags, and unique coupon codes.

Requirements

• A paid 1ClickPopup plan (Launch or above). Mailchimp is a premium integration and not available on the Always Free plan.
• A Mailchimp account with an active API key.

Step 1: Get your Mailchimp API key

1. Log in to your Mailchimp account
2. Go to Profile → Extras → API Keys
3. Create a new API key (or use an existing one)
4. Copy the API key

Step 2: Connect Mailchimp in 1ClickPopup

You can connect Mailchimp from two places – both open the same configuration modal:

From the Settings page: Go to Settings → Integrations tab → click Connect on the Mailchimp card.

From inside a campaign: Open your campaign → Settings tab → scroll to Integrations → click Add integration → select Mailchimp.

In the connection modal:

1. Paste your API key
2. Select an Audience from the dropdown – this is your default audience for all campaigns
3. Click Connect

This connection is shared across all campaigns. If you update the API key or default audience, the change applies everywhere.

Step 3: Configure per campaign (optional)

After connecting, you can customize Mailchimp settings for individual campaigns:

1. Open your campaign → Settings tab → Integrations
2. Click Edit next to Mailchimp

In the campaign-level modal you can:

• Override the default audience – select a different Mailchimp audience for this specific campaign
• Review field mappings – the modal shows how your campaign's form fields map to Mailchimp merge tags. Standard fields (email, tags) map automatically. Discount code and custom fields require matching merge tags to be created in your Mailchimp audience first – see the "Setting up custom fields" section below.

Turning Mailchimp off for a specific campaign: Uncheck the checkbox next to Mailchimp in the Integrations list on the campaign's Settings tab. The integration stays connected globally but won't sync subscribers from that campaign.

Setting up custom fields for Mailchimp

Unlike Klaviyo, Mailchimp does not automatically create custom fields during sync. If you're using custom form fields in your campaign (e.g., a date field, a radio button question), or if you want to sync discount codes, you need to set them up in Mailchimp first:

1. In Mailchimp, go to your Audience → Settings → Audience fields and merge tags
2. Add a new field for each custom field you want to sync – including a DISCOUNTCODE field if your campaign generates unique discount codes
3. Set the field type to Text – this is required for all custom fields synced from 1ClickPopup (email and phone have their own types in Mailchimp, but everything else must be Text)
4. Make sure the merge tag name matches what you configure in the 1ClickPopup field mapping

Important: If your Mailchimp audience has required fields that don't exist in your 1ClickPopup campaign form, the sync will fail. Every required field in Mailchimp must have a matching field in 1ClickPopup with the same name. If you run into sync issues, check for mismatched or missing required fields first.

What gets synced

When a visitor signs up through your popup, 1ClickPopup syncs the following to Mailchimp:

• Email address (always)
• Custom field values (mapped to Mailchimp merge tags – must be set up in Mailchimp first)
• Tags (campaign tags sync automatically so you can identify which campaign captured each subscriber)
• Discount code (if a unique code was generated – requires a DISCOUNTCODE merge tag in your Mailchimp audience)

Things to know

Subscribers sync in addition to Shopify. Connecting Mailchimp doesn't replace the automatic Shopify Customers sync – subscribers go to both platforms.

Double opt-in affects timing. If double opt-in is enabled in 1ClickPopup, the subscriber syncs to Mailchimp only after they click the confirmation link. Note that Mailchimp also has its own double opt-in setting – make sure you're not requiring confirmation twice (once in 1ClickPopup and again in Mailchimp).

The connection is global, overrides are per campaign. The API key and default audience are shared across all campaigns. You can override the audience and field mappings per campaign, or disable Mailchimp for specific campaigns.

Custom fields must exist in Mailchimp before syncing. Unlike Klaviyo (which creates custom properties automatically), Mailchimp requires you to add fields to your audience manually. All custom fields must be set to the Text type.

Unsubscribed emails can't be re-synced. If an email address was previously added to your Mailchimp audience (by 1ClickPopup or any other source) and that person unsubscribed, 1ClickPopup cannot sync them back – even if they sign up again through a different campaign. This is a Mailchimp restriction. The subscriber would need to re-subscribe directly through Mailchimp.

If subscribers aren't syncing, check your API key and field setup. An expired key, missing required fields, or incorrect field types will silently prevent syncing. See My subscribers aren't syncing to Klaviyo or Mailchimp for more troubleshooting steps.

Mailchimp audience vs. list. Mailchimp renamed "lists" to "audiences" – they're the same thing. When we refer to choosing an audience, it's the same as selecting a list.