Advanced Duplicate Lead Prevention Rule

Problem

Standard duplicate rules can be too rigid. Sometimes you need to check for variations in email addresses (e.g., gmail.com vs. googlemail.com) or phone numbers, which is not possible out-of-the-box.

Solution Overview

This solution is a single, powerful Validation Rule formula. It uses VLOOKUP on a custom object containing common email domain variations and REGEX to normalize phone numbers before checking for duplicates using a unique key.

How to Deploy

1. Create the custom object for email domain mappings.
2. Populate it with data.
3. Create the Validation Rule on the Lead object using the provided formula.
4. Activate the rule.