Duplicate Killer – Stop Duplicate Form Submissions in WordPress (CF7, Elementor, Formidable, WPForms, Breakdance)

Duplicate Killer prevents duplicate form submissions in WordPress.

If your forms receive the same email address multiple times, fake leads, or repeated submissions, this plugin blocks them instantly.

Choose which fields must be unique (email, phone, text) and block duplicate entries automatically — without changing your form design or user experience.

Duplicate Killer works silently in the background and integrates seamlessly with popular WordPress form plugins and page builders.

In the free version, duplicate protection rules are applied globally to all forms of the selected plugin.

Duplicate Killer PRO allows you to define different rules, messages and limits for each form.

Supported Plugins

• Elementor Forms
• Contact Form 7
• Formidable Forms
• WPForms Lite
• Forminator
• Ninja Forms
• Breakdance Page Builder Forms

Key Features

✔ Prevent duplicate form submissions without CAPTCHA ✔ Works with existing forms – no changes required ✔ Prevent duplicate submissions by Email, Phone or Text fields ✔ Stop duplicate emails and repeated leads ✔ One global error message for all forms (Free version) ✔ Optional IP-based duplicate protection ✔ Store unique entries securely in your WordPress database ✔ Automatically store uploaded files from Contact Form 7 ✔ Lightweight, fast and easy to configure

Common use cases

• Prevent duplicate leads in contact and lead generation forms
• Keep CRM and email lists clean
• Block repeated event registrations with the same email

Ninja Forms

• Prevent duplicate submissions by Email, Phone or Text fields
• Clean validation messages
• No form design changes required

NEW: Formidable Forms Support

Duplicate Killer now fully supports Formidable Forms and helps you stop duplicate form submissions in WordPress.

You can prevent duplicate entries in Formidable Forms contact forms and advanced forms by enforcing unique fields such as email address, phone number, or text fields.

This feature works with Formidable Forms native fields, requires no additional configuration.

Does not affect form design or user experience.

NEW: Elementor Forms Support

Duplicate Killer now fully supports Elementor Forms.

You can prevent duplicate submissions in Elementor contact forms, lead forms and popups by enforcing unique values such as email or phone number.

This feature works with Elementor’s native form widget and requires no additional configuration.

Plugin Integrations

Contact Form 7

• Limit submissions by Email, Phone or Text fields
• Custom validation message for duplicate entries
• Automatically store uploaded files locally

Elementor Forms

• Prevent duplicate submissions on Elementor native forms
• Works with contact forms, lead forms and popups
• Seamless integration without modifying form structure

Forminator

• Select unique fields (Email, Phone, Text)
• Warn users when a value has already been submitted

WPForms Lite

• Prevent duplicate entries without changing form layout
• Clean and simple validation messages

Breakdance Page Builder Forms

• Prevent duplicate submissions on Breakdance native forms
• IP-based validation for cleaner data
• Fully compatible with Breakdance UI

Free vs Pro

Free Version

• Global duplicate protection rules applied to all forms
• One global error message for duplicate submissions
• Global IP-based submission limits
• Unique entries per user (cookie-based)
• Supports multiple form plugins

Duplicate Killer PRO

• Per-form duplicate protection rules
• Custom error message for each form
• Different IP limits per form
• Unique entries per user, configurable per form
• Designed for sites with multiple forms and different submission needs
• Duplicate Killer PRO is ideal for sites with multiple forms and different audiences.

When to use Duplicate Killer

Use this plugin if you receive repeated submissions with the same email, phone number or text values. If you only need basic spam protection, a CAPTCHA plugin may be enough.

When should I use Duplicate Killer PRO?

Use the PRO version if your site has multiple forms with different purposes — for example a contact form, a registration form and a newsletter signup — and each one needs different duplicate submission rules.