How to Connect Mailchimp

ACS connects to Mailchimp using your API key and audience ID to automatically send campaigns and sync engagement analytics.

What You'll Get

• Automated campaign delivery to your Mailchimp audience
• Historical analytics backfill on first connection
• Weekly analytics sync: opens, clicks, open rate, click rate, bounce rate

Prerequisites

• A Mailchimp account (Essentials plan or higher recommended for full API support)
• Your Mailchimp API Key, Audience ID, and server prefix

Step 1: Get Your Mailchimp API Key

1. Log into Mailchimp and click your account name in the bottom-left corner
2. Go to Account & billing → Extras → API keys
3. Click Create A Key, give it a label such as "ACS", then copy the key

Your API key ends with a server prefix like -us21 or -us14. Note this suffix — you will need it.

Step 2: Find Your Audience ID

1. In Mailchimp, go to Audience → All contacts
2. Click Settings → Audience name and defaults
3. Your Audience ID is listed on this page (a short alphanumeric string)
4. Copy it

Step 3: Connect in ACS

1. In ACS, go to Settings → Integrations
2. Under Publishing Destinations, click Set Up for your Newsletter channel
3. Select Mailchimp from the provider list
4. Enter your API Key, Audience ID, and Server Prefix (the suffix at the end of your API key, e.g., us21)
5. Click Connect

Analytics Backfill

On first connection, ACS retrieves your historical campaign performance data from Mailchimp and populates your Analytics dashboard automatically.

Disconnecting Mailchimp

Go to Settings → Integrations → Newsletter → Edit and remove your Mailchimp credentials.

Troubleshooting

Authentication errors Regenerate your API key in Mailchimp and update it in ACS. Confirm the server prefix matches the suffix at the end of your API key.

Wrong audience receiving campaigns Double-check your Audience ID. Mailchimp accounts can have multiple audiences — confirm you have selected the correct one.

Analytics not populating Mailchimp analytics finalize 24–48 hours after a campaign is sent. Allow one full weekly cycle after connecting before expecting complete data.