Beschrijving
Duplicate Killer – Stop Duplicate Form Submissions in WordPress (CF7, Elementor, Formidable, WPForms, Breakdance)
Beschrijving
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.
Schermafbeeldingen
Installatie
- Install Duplicate Killer from the WordPress Plugins screen or upload it to
/wp-content/plugins/. - Activate the plugin from the Plugins menu.
- Open Duplicate Killer from your WordPress admin dashboard.
- Select your form plugin and choose which fields must be unique.
FAQ
Does this plugin block bots or spam?
Duplicate Killer focuses on preventing duplicate form submissions and entries. It works alongside spam or CAPTCHA plugins and does not replace them.
Will this slow down my site?
No. Duplicate Killer performs lightweight database checks only on form submission and has no impact on frontend performance.
Why should I use Duplicate Killer?
Duplicate Killer prevents duplicate emails and repeated form submissions, helping you keep your leads and contact data clean.
How does Duplicate Killer work?
When a form is submitted, selected field values are stored in the database. If the same value is submitted again, the submission is blocked and a validation message is shown.
Can multiple users submit the same value?
Yes. In the PRO version, you can enable “Unique entries per user”, allowing multiple users to submit the same value while blocking repeat submissions from the same user.
Does it affect form design or styling?
No. Duplicate Killer works in the background and does not change your form appearance.
Does it work with Elementor Forms?
Yes. Duplicate Killer fully supports Elementor Forms.
Does this plugin work with existing spam protection plugins?
Yes. Duplicate Killer works alongside spam and CAPTCHA plugins and focuses only on preventing duplicate form submissions.
Beoordelingen
Bijdragers & ontwikkelaars
“Duplicate Killer – Stop Duplicate Form Submissions in WordPress (CF7, Elementor, Formidable, WPForms, Breakdance)” is open source software. De volgende personen hebben bijgedragen aan deze plugin.
BijdragersInteresse in ontwikkeling?
Bekijk de code, haal de SVN repository op, of abonneer je op het ontwikkellog via RSS.
Changelog
1.4.7
- New: Full Ninja Forms support – block duplicate submissions before entries are saved.
- Major upgrade: Cookie engine fully rewritten for better performance and reliability.
- Improved compatibility with cache plugins and strict Content Security Policies (CSP).
- Smarter cookie-based uniqueness logic, applied only when enabled per form.
- Internal optimizations preparing support for additional form plugins.
1.4.6
- New: Formidable Forms support – stop duplicate form submissions by email or other fields.
- Prevent duplicate entries by email, phone, or text fields in Formidable Forms.
- Improved compatibility and stability across supported form plugins.
1.4.5
- New feature: Duplicate protection for Elementor Forms
1.4.4
- Bug fix: Undefined array key Forminator
1.4.3
- Bug: Problem with table creation
1.4.2
- Support Number field on Forminator
1.4.1
- Tested up to WordPress 6.9
1.4.0
- Feature: Added support for forms built with Breakdance Page Builder.
1.3.1
- Feature: Automatically store uploaded files from the form (CF7) on your server
1.3.0
- Tested up to 6.8.1
- Feature: Restrict form entries based on IP address
1.2.3
- Feature: Store CF7 files submitted
1.2.2
- Bug: Problem with table creation
- Feature: Add form date submission
1.2.1
- Feature: Store CF7/Forminator/WPForms submissions to your WordPress database
- Tested up to 6.7.2 WordPress
1.2.0
- Bug: Fixed – Custom HTML in CF7 form – issue with detection
1.1.9
- Bug: Fixed only first 3 forms are showing in the “WPForms forms list”
1.1.7
- Bug: Fixed style sheet.
1.1.6
- Bug: Prevent empty values from being detected as duplicate entries.
1.1.5
- Interface to manage the saved values in your WordPress database.
1.1.4
- Duplicate Killer will prevent the entries from being added into CFDB7(Contact Form 7 Database Addon) plugin.
- Tested up to 6.4.1 WordPress’
1.1.3
- Fixed PHP Warning Undefined array key at CF7 function
- Tested up to 6.3.1 WordPress’
1.1.2
- Tested up to 6.1.1 WordPress’
1.1.1
- Fix bug at feature ‘Unique entries per user’
1.1.0
- New feature – Unique entries per user
- New style navigation for better UX
1.0
- First public release









