Question from Reddit user:
Can information about which mailchimp group(s) a subscriber is part of can be synced to HubSpot?
For example, I have two groups named “Red Mail” and “Blue Mail”.
Someone who is part of the “Red Mail” group should show up as such in HubSpot.
Anyone who is part of both should show up as subscribers of both “Red Mail” and “Blue Mail”
Furthermore, someone who unsubscribes from “Red Mail” should no longer be shown as part of the group in HubSpot.
Answer from Nabil:
The short answer is:
You are correct to focus on Mailchimp Group membership, as the standard HubSpot-Mailchimp integrations, even the paid Data Sync feature, do not support syncing Group membership changes in the two-way, dynamic manner you require.
Specifically, they cannot automatically update HubSpot when a contact is added to or unsubscribes from a Mailchimp Group.
The only reliable and cost-effective solution for this specific requirement is a custom, API-driven sync.
This involves using the MailChimp API to monitor Group changes and then immediately pushing those updates to a custom multi-select or checkbox property in HubSpot using the HubSpot API.
The long answer is:
Your requirement for a real-time, bidirectional sync of Mailchimp Group membership (like “Red Mail” and “Blue Mail”) to a corresponding field in HubSpot, including handling unsubscriptions, perfectly highlights the core limitation of standard SaaS integrations.
HubSpot’s native and Data Sync integrations are generally designed for basic contact and activity syncing, and they explicitly exclude Mailchimp Groups and Tags from their dynamic sync capabilities, though a one-way sync of Tags to a HubSpot text field is sometimes possible with paid Operations Hub.
Middleware like Zapier can technically achieve this, but it quickly becomes expensive and complex to maintain multiple Zaps for every single subscribe and unsubscribe event for every single Group you have.
The superior and more efficient long-term solution is to create a lightweight, API-driven application.
This involves setting up webhooks within Mailchimp to listen for specific events, primarily the subscribe and unsubscribe events that include Group data.
When one of these events is triggered in Mailchimp, the webhook sends a real-time notification to a server-side environment like Stape or Google Cloud Platform.
This simple script then extracts the contact’s email and the Group information (“Red Mail” or “Blue Mail”) and uses the HubSpot API to update a custom contact property in HubSpot.
By creating a custom multi-select checkbox property in HubSpot to mirror your Mailchimp Groups, the script can simply check or uncheck the relevant box using a single, targeted API call, ensuring that when a contact unsubscribes from “Red Mail” in Mailchimp, the script instantly updates the contact record in HubSpot to remove that value.
While this involves a small initial development cost to write the script, the ongoing execution cost is extremely low, especially if hosted on a minimal-usage platform like Google Cloud Functions or Stape, making it a highly scalable and often cheaper solution than continuous, high-volume Zapier subscriptions, while giving you complete control over the data mapping and synchronization logic.
Google Tag Manager is not directly involved in this server-to-server data sync, but it remains your tool for managing any client-side Standard Events related to form submissions or list sign-ups that feed into the Mailchimp system in the first place.
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