Restflow.io

## Introduction

Email marketing is a cornerstone of modern marketing strategies. However, even the most compelling email campaigns can fail if emails don’t reach recipients’ inboxes. Monitoring email deliverability in real time enables marketing teams to promptly identify and address issues such as bounces, spam complaints, or delays. This ensures high engagement rates and protects sender reputation.

This article walks you through building a real-time email deliverability monitoring workflow using n8n, an open-source automation tool, integrated with popular services like Gmail (or any SMTP email service), Google Sheets, and Slack for alerting. The solution benefits marketing teams, operations specialists, and startup CTOs responsible for maintaining email health and campaign success.

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## What Problem Does This Automation Solve?

**Problem:** Marketers often send bulk emails without immediate feedback on deliverability issues, causing undetected bounce rates and spam complaints to damage sender reputation over time.

**Solution:** A real-time monitoring workflow that:
– Detects bounce messages and spam complaints automatically
– Logs deliverability metrics
– Sends instant alerts to marketers or ops teams
– Provides a central dashboard for trends and analysis

**Who Benefits?**
– Marketing teams ensuring campaigns reach inboxes
– Operations teams maintaining sender reputation
– Automation engineers tasked with campaign health monitoring

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## Tools and Services Integrated

– **n8n:** The automation orchestration platform used to build and run the workflow.
– **Email Service (Gmail/SMTP provider):** Receiving and sending emails.
– **Google Sheets:** Stores logs of email deliverability metrics and bounce reasons.
– **Slack:** Real-time alert channel for deliverability issues.

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## Overview of the Workflow

1. **Trigger:** New emails (including bounce or complaint notifications) are received in a monitored inbox.
2. **Parse Email:** Extract metadata such as subject, sender, bounce reason, complaint details.
3. **Analyze Deliverability Status:** Determine if email is delivered, bounced, or marked as spam.
4. **Log Data:** Record the event in Google Sheets for trending and historical analysis.
5. **Alert:** Send real-time notifications to Slack if critical issues arise.

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## Step-by-Step Technical Tutorial

### Prerequisites

– n8n instance running (self-hosted or cloud)
– Gmail account or similar IMAP accessible mailbox
– Google Sheets API enabled and credentials set
– Slack workspace and webhook URL or API token

### Step 1: Set Up Email Trigger in n8n

– Use the **IMAP Email** node configured to connect to your monitored mailbox.
– Set the node to watch for new emails periodically (e.g., every 1 minute).
– Configure folder (e.g., INBOX) and ensure that read emails are marked or moved to avoid duplicates.

**Tip:** Use dedicated inbox or folder for bounce emails to simplify filtering.

### Step 2: Filter and Parse Bounce Emails

– Add a **IF** node to check if the email subject or sender matches bounce or complaint patterns.
– Bounce emails often come from MAILER-DAEMON or contain keywords like “Delivery Status Notification”.
– Use a **Function** node or n8n’s **Email Parser** to extract:
– Original recipient email
– Bounce reason (e.g., mailbox full, user unknown)
– Timestamp

**Example Function snippet:**

“`javascript
const body = $json[“textPlain”] || “”;
const bounceReasons = [“mailbox full”, “user unknown”, “blocked”]; // extend as needed
let reason = “Unknown”;
for (const r of bounceReasons) {
if (body.toLowerCase().includes(r)) {
reason = r;
break;
}
}
return [{ json: { reason } }];
“`

### Step 3: Log Deliverability Data in Google Sheets

– Use the **Google Sheets** node:
– Authenticate using your Google service account or OAuth credentials.
– Specify the spreadsheet and worksheet where you want to log data.
– Map data fields: date/time, recipient email, bounce reason, subject.

– This log becomes your source of truth for deliverability trends.

### Step 4: Send Alerts to Slack

– Add a **Slack** node configured with your Slack API token or incoming webhook.
– Prepare a formatted message including:
– Email recipient
– Bounce reason
– Subject
– Time
– Use conditional logic (via an **IF** node) to only alert on critical bounce reasons or spam complaints.

**Example Alert:**

“🚨 Email to `john@domain.com` bounced due to: mailbox full at 2024-06-15 14:22”

### Step 5: Mark or Move Processed Emails

– To avoid re-processing, use another **IMAP Email** or **Function** node to mark the message as read or move it to a “Processed” folder.

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## Common Errors and Tips for Robustness

– **Email Parsing Accuracy:** Bounce messages vary by provider. Maintain a list of bounce patterns and update parsing logic regularly.
– **API Rate Limits:** Google Sheets and Slack have API limits. Batch inserts or alerts if volume is high.
– **Authentication Expiry:** Ensure OAuth tokens are refreshed or service account permissions maintained.
– **Duplicate Processing:** Make sure emails are marked or moved after processing.
– **Delayed Incoming Bounces:** Some bounces can arrive hours or days late. Consider backfilling.

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## Scaling and Adaptation

– **Integrate with CRM:** Extend the workflow to update contact status or trigger suppression in HubSpot or similar tools.
– **Dashboard Visualization:** Connect Google Sheets data to Data Studio or Tableau for visual analytics.
– **Multi-Channel Alerts:** Add SMS or email alerts alongside Slack.
– **Add Whitelisting and Blacklisting:** Automate suppression of bad addresses.
– **Support Multiple Email Providers:** Expand to monitor multiple sender inboxes.

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## Summary

By leveraging n8n and integrating your email inbox with Google Sheets and Slack, marketing teams can build an actionable and scalable real-time email deliverability monitoring system. This workflow empowers rapid identification of bounces and complaints, helping maintain high sender reputation and campaign effectiveness.

Continuous monitoring combined with automated alerts drastically reduces the risk of unseen deliverability problems. With incremental improvements in parsing and integration, this workflow can evolve into a comprehensive email health monitoring platform.

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## Bonus Tip

For increased accuracy and efficiency, consider integrating third-party email deliverability APIs such as Postmark, SendGrid, or Mailgun. Many provide webhooks for bounce and complaint notifications which can directly trigger n8n workflows — bypassing the need for email parsing entirely and increasing reliability.

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By implementing this approach, startup teams can proactively safeguard their email campaigns, a crucial business asset, with minimal manual effort and maximal automation sophistication.