List Armor

Mailchimp Integration

Automatically sync unsubscribes, bounces, and complaints from Mailchimp to your suppression lists.

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Overview

The Mailchimp integration uses webhooks to automatically add email addresses to your suppression lists when subscribers unsubscribe, get cleaned (bounced), or file complaints.

Real-Time Sync

Events processed within seconds

Secure Webhooks

Secret key verification

Audience Sync

Per-audience webhooks

Prerequisites

  • A Mailchimp account with at least one audience
  • Admin or Manager access to the Mailchimp audience
  • A List Armor campaign with at least one suppression list

Setup in List Armor

  1. Navigate to your campaign and click ESP Integrations
  2. Click Add Integration and select Mailchimp
  3. Choose the Target Suppression List where opt-outs will be added
  4. Configure which events to auto-suppress:
    • Hard bounces (cleaned contacts) — recommended
    • Spam complaints — recommended
    • Unsubscribes — recommended
  5. Add a Webhook Secret for verification (you'll use this in Mailchimp)
  6. Save the integration and copy the Webhook URL

Configure Mailchimp

  1. Log in to your Mailchimp account
  2. Navigate to Audience → All contacts
  3. Click Settings → Webhooks
  4. Click Create New Webhook
  5. Paste your List Armor webhook URL in the Callback URL field
  6. Select the events to trigger webhooks:
    • Subscribes — Optional (not used for suppression)
    • Unsubscribes — Recommended
    • Profile Updates — Optional
    • Cleaned — Recommended (bounces)
    • Email Changed — Optional
    • Campaigns — Not needed
  7. Under "Only send updates when", ensure both options are unchecked to receive all events
  8. Click Save
Note: Mailchimp webhooks are configured per-audience. If you have multiple audiences, create a webhook for each one pointing to the same List Armor URL.

Supported Events

Mailchimp Event List Armor Action Default
cleaned (hard bounce) Add to suppression list Enabled
cleaned (abuse) Add to suppression list Enabled
unsub Add to suppression list Enabled
subscribe Logged only (not suppressed) N/A

Testing

After configuring the webhook, verify it's working:

  1. Add a test subscriber to your Mailchimp audience
  2. Unsubscribe the test address from the audience
  3. Check your List Armor integration for the Last webhook received timestamp
  4. Verify the email appears in your target suppression list
Tip: Use a test email you control (like a +alias address) so you can easily test the full flow.

Troubleshooting

  • Verify the webhook is saved in Mailchimp
  • Check that "Unsubscribes" and "Cleaned" events are selected
  • Ensure the webhook URL is correct
  • Check Mailchimp's webhook activity for errors

  • Mailchimp requires HTTPS URLs
  • Verify the URL is publicly accessible
  • Check that the URL doesn't have typos
  • Try the URL in a browser to confirm it responds

  • Check that both "API" and "Admin" sources are enabled in webhook settings
  • Verify all desired event types are checked
  • If you have multiple audiences, ensure each has a webhook configured

Need Help?

Having trouble with your Mailchimp integration? Our support team can help.

Contact Support