Duplicate Killer – Prevent Duplicate Form Submissions

How well this listing is tuned to rank in WordPress.org search, on the factors an owner controls. Not popularity, optimization.

Directory rank vs rivals

wp.org popularity rank over time · higher is better · when a rival's line climbs above yours, they've overtaken you

How often this plugin actually ships. A steady rhythm is the maintenance signal a single "last updated" date can't show.

Share of active installs on each version of this plugin · 47% run the current release. Green is the current release; a big slice on older versions is a user base that has stopped updating.

Refined from the date this plugin crossed into its current band.

No paid tier is visible, so we don't put a figure on revenue or sale value: that would be guessing. The install base is a real asset to an acquirer, just not one public data lets us price. A small install base leaves thin data to model from. A declining trend compresses what a buyer would pay.

Reviewers say it fixes duplicate form submissions right out of the box, including a Contact Form 7 double-email problem, and they're happy with the support.

1. ★★★★★ jeng22

   2.4y ago

   Plugin is straightforward and the support is really responsive and helpful.

   Read on wp.org ↗
2. ★★★★★ hambad

   2.5y ago

   There seems to be an issue with CF7 where duplicate emails are sent out, and the forms render errors/loading spinners twice as well. I’ve done a good bit of research and looked everywhere, but had no luck finding a fix for this. This plugin resolved the issue straight away with no configuration needed! Thank you!

   Read on wp.org ↗
3. ★★★★★ peterlovescola

   2.9y ago

   This solves my duplicate entries headache – works as intended. Thanks!

   Read on wp.org ↗

Automated install-time checks, tested on PHP 8.1.12 · WP 7.0

Growth timeline

Install-tier crossings we have observed, and how long each tier took to outgrow

1. 2024-09-30 900+ → 1K+ up after 38 days in tier
2. 2024-08-23 800+ → 900+ up after 28 days in tier
3. 2024-07-26 700+ → 800+ up after 29 days in tier
4. 2024-06-27 600+ → 700+ up after 22 days in tier
5. 2024-06-05 500+ → 600+ up after 34 days in tier
6. 2024-05-02 400+ → 500+ up after 40 days in tier
7. 2024-03-23 300+ → 400+ up after 65 days in tier
8. 2024-01-18 200+ → 300+ up after 62 days in tier

Competes with

The plugins that solve the same job, ranked by shared tags then reach, closest match first. The letter on the right is each plugin's health grade (A best, F worst).

• Google for WooCommerce 800K+ installs · 2.8★ · 1 shared tag B
• WooCommerce PayPal Payments 800K+ installs · 2.9★ · 1 shared tag B
• WooCommerce Stripe Payment Gateway 700K+ installs · 3.1★ · 1 shared tag B
• Database Addon for Contact Form 7 – CFDB7 600K+ installs · 5.0★ · 1 shared tag A
• WooCommerce Tax (formerly WooCommerce Shipping & Tax) 500K+ installs · 2.2★ · 1 shared tag C
• WooCommerce Legacy REST API 400K+ installs · 2.2★ · 1 shared tag D

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Duplicate Killer – Prevent Duplicate Form Submissions: 1K+ active installs, 5.0★ (3 reviews). Plugin Pulse (WP Mayor), as of 2026-08-29. https://plugins.wpmayor.com/plugin/duplicate-killer