Automate Mautic Unsubscribe Handling with Gmail & n8n

Opening Problem Statement

Meet Sarah, a marketing manager overseeing a high-volume email campaign using Mautic. Each day, she receives dozens of automated unsubscribe requests via her Gmail inbox. These emails clutter her inbox and require tedious manual work: extracting the senders email, verifying their Mautic contact record, removing them from active newsletter lists, and adding them to unsubscribe segments. This process is slow, error-prone, and wastes hours weekly that could be spent on campaign strategy or content creation.

Manual processing also risks compliance failures. If an unsubscribe request is missed or mishandled, it could lead to frustrated contacts, spam complaints, or legal repercussions under privacy laws like GDPR. Sarah needs a reliable automation that efficiently handles unsubscribe emails, updating Mautic accurately and responding promptly.

What This Automation Does

This workflow runs every minute, checking Sarahs Gmail for unsubscribe emails and automates the entire unsubscribe process with Mautic. When triggered by an unsubscribe message, it performs:

• Extracts the senders email address reliably from the Gmail “From” field, even if formatted with extra characters.
• Deduplicates email addresses to avoid duplicate processing for multiple unsubscribe emails.
• Searches Mautic for the contact linked to the extracted email.
• Verifies the unsubscribe email is legitimate by checking content and sender address to prevent false triggers.
• Adds the contact to an “Unsubscribed” segment and removes them from the active newsletter segment in Mautic.
• Replies to the unsubscribe email with a polite confirmation message.

By automating these, Sarah saves hours weekly and eliminates manual errors, while ensuring compliance with unsubscribe requests.

Prerequisites 

• 📧 A Gmail account set up with OAuth2 credentials configured in n8n for triggers and replying
• 🔑 Mautic account with OAuth2 authentication for API access to contact segments
• ⚙️ An n8n automation platform account to create and run the workflow

Optionally, if you prefer control, you can self-host n8n using platforms like Hostinger.

Step-by-Step Guide

Step 1: Configure Your Email Address and Unsubscribe Message

Click the Edit Fields node → In the parameters panel, set emailAddress to your Gmail address (e.g., [email protected]) and unsubscribeMessage to the reply you want to send, such as “Your have successfully opted out from our marketing campaigns. Please reply if you believe this is an error.”
You should see these fields saved, serving as reference for later logic.
Common mistake: Not updating the emailAddress in this node causes the workflow to misidentify unsubscribe emails.

Step 2: Set up Gmail Trigger Node

Click the Gmail Trigger node → Under credentials, select your Gmail OAuth2 account.
Configure the polling to run every minute to catch unsubscribe emails promptly.
You should see this node activate and show incoming Gmail emails based on your filters.
Common mistake: Not authorizing Gmail correctly or missing the “includeSpamTrash” filter can cause missed unsubscribe emails.

Step 3: Identify Automated Unsubscribe Emails

Open the Is automated unsubscribe? IF node → Set two string conditions:
– Check if the “To” field contains “unsubscribe”.
– Confirm the “From” is not equal to the email configured in Edit Fields.
This prevents accidental triggers on emails from yourself.
You should see emails correctly filtered as candidates for automated unsubscribes.
Common mistake: Incorrect string operations can block valid emails or trigger false positives.

Step 4: Extract the Email Address from the ‘From’ Field

Open the Extract Email from ‘From’ Field code node → Review the JavaScript:

var fromField = $input.item.json.From;
var extractedEmail;
if (fromField.includes('<') && fromField.includes('>')) {
  var regex = /[^< ]+(?=>)/g;
  extractedEmail = fromField.match(regex)[0];
} else {
  extractedEmail = fromField;
}
return {json: {extractedEmail}};

This code extracts the real email address whether it is surrounded by “<>” or plain.
Expected output is a clean email address in the field extractedEmail.
Common mistake: Modifying the regex without full understanding can cause extraction errors.

Step 5: Remove Duplicate Emails

Open the Extract Unique Email Addresses code node.
It collects all extracted emails and converts them to a unique set to prevent processing duplicates:

const inputData = $input.all();
const uniqueEmailsSet = new Set();
inputData.forEach(item => {
  uniqueEmailsSet.add(item.json.extractedEmail);
});
const uniqueEmailsArray = Array.from(uniqueEmailsSet).map(email => {
  return { json: { extractedEmail: email } };
});
return uniqueEmailsArray;

This ensures efficient processing.
Expected output is a list of unique emails.
Common mistake: Changing data format breaks Mautic lookup.

Step 6: Fetch Mautic Contact Based on Email

Open the Get Mautic Contact ID from Email Address node → Under parameters, ensure the search is set to email:{{ $json["extractedEmail"] }}.
Use your Mautic OAuth2 credentials.
You should get the contact details if found.
Common mistake: Wrong OAuth2 credentials lead to empty searches.

Step 7: Check If Contact Exists

Open the If Contact Exists in Mautic node → It checks whether the id field is present.
Only if contact exists, the automation continues to update segments; otherwise, it replies politely but does not update segments.
Expected outcome: Only valid contacts are processed downstream.
Common mistake: Misconfiguring the check causes false positives or missed contacts.

Step 8: Update Mautic Segments for Unsubscribe

Find the Add to unsubscribed segment node → It adds the contact ID to segment 3 designated for unsubscribed contacts.
The Remove newsletter segment node removes the contact from segment 1 (active newsletter).
Use your Mautic OAuth2 credentials.
Expected outcome: Contact segment lists update instantly.
Common mistake: Segment IDs mismatch causes incorrect segment membership.

Step 9: Reply to the Unsubscribe Email

Open the Reply Unsubscribe Message Gmail node → It sends your confirmation message back to the requester.
Uses the message body from the earlier Edit Fields node.
Expected outcome: Senders receive prompt confirmation.
Common mistake: Not mapping messageId properly results in reply failures.

Customizations ✏️

• Change the confirmation reply message: Edit the unsubscribeMessage string value in the Edit Fields node to personalize or translate.
• Modify segment IDs: Adjust segment IDs in “Add to unsubscribed segment” and “Remove newsletter segment” nodes to match your Mautic setup or add new segment operations.
• Enable Do Not Contact List: Currently disabled, activate the “Add to Do Not Contact List” node to further block contacts from future campaigns by enabling the node and configuring any additional fields.
• Alter Gmail filter frequency: Change polling in the Gmail Trigger node frequency from every minute to another suitable interval balancing real-time processing and API limits.
• Expand unsubscribe criteria: Add more conditions in the Is automated unsubscribe? IF node to capture varied unsubscribe email patterns.

Troubleshooting 🔧

Problem: “No credentials returned” error in Mautic node

Cause: OAuth2 credentials are missing, expired, or incorrectly set.
Solution: Go to each Mautic node → Credentials section → Re-select or re-authenticate your OAuth2 account.
Test connection before deploying.

Problem: Gmail Trigger does not fire or misses emails

Cause: Gmail API limits or filter misconfiguration.
Solution: Verify Gmail OAuth2 credentials.
Check box “includeSpamTrash” to true if your unsubscribe emails land in spam.
Adjust poll interval if hitting API limits.

Problem: Contacts not added/removed from segments

Cause: Segment ID mismatch or insufficient permissions.
Solution: Confirm segment IDs in Mautic dashboard.
Ensure your OAuth2 user has API rights.
Test with known contact.

Pre-Production Checklist ✅

• Verify Gmail OAuth2 credentials and test trigger with unsubscribe emails.
• Confirm Mautic OAuth2 credentials and successful API calls using test contacts.
• Check segment IDs in Mautic to match those configured in nodes.
• Run test emails from a separate address to validate extraction and processing.
• Confirm workflow connections and IF node conditions.
• Backup your n8n workflow JSON and Mautic data before production deployment.

Deployment Guide

Activate the workflow in n8n by clicking the Activate button.
Verify the Gmail trigger fires on new unsubscribe emails.
Monitor workflow executions in the n8n dashboard logs for errors.
Use error handling or webhook notifications for monitoring if preferred.
Adjust polling intervals to maintain API quota management.
This workflow requires minimal manual intervention once live, ensuring ongoing automated unsubscribe compliance.

FAQs

Q: Can I use Outlook instead of Gmail for the trigger?
A: This specific workflow is built on Gmail Trigger and reply nodes, so it requires Gmail OAuth2 credentials. To use Outlook, you would need to replace those nodes with Outlook equivalents and adjust logic accordingly.

Q: Does this consume a lot of API credits on Mautic?
A: The workflow performs minimal API calls per unique email and works with low frequency (every minute). This should be efficient for most Mautic plans.

Q: Is my contact data secure?
A: Yes, OAuth2 authentication ensures secure API communication. Only necessary contact data is processed temporarily for automation.

Q: Can this handle hundreds of unsubscribe emails per hour?
A: Yes, with suitable polling intervals and server resources, n8n can handle high volumes. Consider queuing or batching if volume increases significantly.

Conclusion

By following this detailed guide, youve built a reliable n8n automation that streamlines handling unsubscribe emails from Gmail into your Mautic CRM. This workflow saves Sarah—and you—valuable hours and prevents costly errors by automating segment management and replies accurately and promptly.

Next, consider extending this automation by integrating webhook triggers from other email services, adding a logging database node for audit trails, or enhancing unsubscribe message personalization with conditional logic or AI nodes.

Youve taken an important step towards a professional email unsubscribe management system that respects your contacts wishes and keeps your marketing compliant.