Send bulk email campaigns with Gmail/SMTP and Postgres reputation-safe timing

Description

Overview
This workflow automates bulk email campaigns with built-in validation, deliverability protection, and smart send-time optimization.

It processes CSV leads, validates emails, enriches data, and schedules campaigns intelligently. Emails are sent using controlled inbox rotation, while engagement tracking and analytics continuously improve performance.

How It Works

Campaign Input
Receives campaign data and CSV leads via webhook.

Lead Processing
Extracts CSV data, splits leads, and validates email format.

Domain & Quality Checks
Verifies domains using MX records and filters invalid leads.

Lead Enrichment
Adds timezone, domain type, and engagement score for better targeting.

Lead Storage
Stores valid leads and separates invalid ones for tracking.

Campaign Execution
Scheduler fetches active campaigns and selects top leads.

Send Optimization
Calculates best send time per lead based on timezone and historical performance, while selecting inboxes within sending limits.

Email Delivery
Waits until optimal time and sends emails using selected inbox.

Tracking & Logging
Logs sent emails and updates inbox usage statistics.

Event Tracking
Captures opens, clicks, replies, and bounces via webhook.

Performance Analytics
Updates campaign stats and analyzes engagement trends.

Continuous Optimization
Updates send-time rules to improve future campaign performance.

Setup Instructions

Connect webhook for campaign and CSV upload
Configure send limits, delays, and MX API
Set up Postgres with required tables
Connect Gmail or SMTP for sending
Configure event webhook for tracking
Enable campaign and analytics schedulers
Test with sample campaign before activating

Use Cases

Running cold email campaigns at scale
Improving email deliverability and sender reputation
Automating lead validation and enrichment
Optimizing send times based on engagement data
Managing multi-inbox outbound systems

Requirements

n8n instance with webhook support
Postgres database
Gmail or SMTP email account(s)
MX record lookup API (e.g., Google DNS)
Email tracking system or webhook integration

Notes

Inbox rotation and throttling help prevent spam and protect reputation.
Engagement-based lead scoring improves campaign performance.
Send-time optimization is continuously refined using real data.
You can extend this workflow with personalization or AI-generated emails.