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.
Free: In the free version, duplicate protection can be enabled for one form per supported plugin.
PRO: Duplicate Killer PRO enables multi-form protection with individual rules and messages per 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
- Protect one form (per supported plugin)
- Global duplicate protection rules (for the protected form)
- One global error message
- Global IP-based submission limits
- Unique entries per user (cookie-based)
Duplicate Killer PRO
- Protect multiple forms
- 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.