Description
Mailster reCaptcha adds Google reCAPTCHA spam protection to Mailster newsletter subscription forms. It uses reCAPTCHA v3, so visitors get a low-friction check instead of a checkbox challenge, while failed verifications are blocked on the server before a signup is accepted.
Use it when bot signups, fake subscribers, or newsletter form spam are polluting your Mailster lists.
This plugin requires Mailster 4.0 or newer and free Google reCAPTCHA site and secret keys. Form submissions send a reCAPTCHA response token to Google for verification.
Why use Google reCAPTCHA with Mailster?
- Stop newsletter signup spam — Verify each protected form submission with Google before Mailster accepts the subscriber.
- reCAPTCHA v3 — Invisible, score-based protection that runs in the background without a “I’m not a robot” checkbox.
- Mailster block forms and legacy forms — Enable captcha per block form in the form editor, or select legacy forms under Newsletter settings.
- Server-side verification — Tokens are checked with Google’s
siteverifyAPI so clients cannot skip the captcha by removing fields. - Custom error message — Show clear feedback when verification fails.
- Optional skip for logged-in users — Disable reCAPTCHA for users who are already signed in to WordPress.
- Loads only when needed — The reCAPTCHA script is enqueued for forms that have captcha enabled, including multiple forms on one page.
How it works
- Install and activate Mailster reCaptcha alongside Mailster.
- Create reCAPTCHA v3 keys in the Google reCAPTCHA admin console.
- Enter your Site Key and Secret Key under Newsletter Settings reCaptcha.
- Enable captcha on the forms you want to protect (legacy form checkboxes in settings, or the Enable reCaptcha panel on each block form).
- On submit, the plugin sends the token to Google and rejects the signup if verification fails.
Prefer a non-Google captcha? You may also try Mailster Cool Captcha for Forms. Addon overview: Use reCaptcha with Mailster.
Additional Info
This plugin requires the Mailster Newsletter Plugin for WordPress 4.0 or newer and Google reCAPTCHA site and secret keys. Protected form submissions are verified via Google’s reCAPTCHA API.
Screenshots
Installation
- Upload the entire
mailster-recaptchafolder to the/wp-content/plugins/directory, or install from the WordPress plugins screen. - Activate the plugin through the Plugins menu in WordPress.
- Make sure Mailster 4.0+ is installed and active.
- Register your site at google.com/recaptcha/admin and create reCAPTCHA v3 keys for your domain.
- Go to Newsletter Settings reCaptcha, enter the Site Key and Secret Key, and save.
- Enable reCAPTCHA on the subscription forms you want to protect:
- Legacy forms: select them on the same settings screen.
- Block forms: edit the form and enable Enable reCaptcha in the form document settings.
FAQ
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Does this plugin work without Mailster?
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No. Mailster reCaptcha is an addon for the Mailster Newsletter Plugin and requires Mailster 4.0 or newer.
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Do I need a Google account or reCAPTCHA keys?
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Yes. You need free reCAPTCHA site and secret keys from the Google reCAPTCHA admin console. Create keys for reCAPTCHA v3 and add the domains where your forms are shown.
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Is this reCAPTCHA v2 or v3?
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This addon uses Google reCAPTCHA v3 (invisible / score-based). It does not show the classic checkbox widget.
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Does it work with Mailster block forms?
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Yes. For block forms, open the form in the editor and enable Enable reCaptcha in the document settings panel. Legacy forms are enabled from Newsletter Settings reCaptcha.
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Is visitor data sent to a third party?
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Yes. To verify a submission, the plugin sends the reCAPTCHA response token to Google’s verification endpoint (
www.google.com/recaptcha/api/siteverify). Google’s reCAPTCHA service also loads in the browser for protected forms. See Google’s reCAPTCHA documentation for how the service works. -
Can I turn off reCAPTCHA for logged-in users?
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Yes. Enable Disable for logged in users on the reCAPTCHA settings screen if you do not want captcha checks for users who are already logged in to WordPress.
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Where can I get support?
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For Mailster and this addon, see mailster.co. For key setup or reCAPTCHA behavior, use Google’s reCAPTCHA docs.
Reviews
Contributors & Developers
“Mailster reCaptcha” is open source software. The following people have contributed to this plugin.
Contributors
Translate “Mailster reCaptcha” into your language.
Interested in development?
Browse the code, check out the SVN repository, or subscribe to the development log by RSS.
Changelog
2.0.2
- improved: packaging and release pipeline for WordPress.org
2.0.1
- fixed: issue with latest block forms plugin not shoing settings page
- tested: up to WordPress 6.3
2.0.0
- Supports now Mailster Block Forms
1.6
- only output script if form has been rendered.
1.5
- updated file structure
1.4.1
- fixed: problem with confirmation if add on is enabled
1.4
- fixed: submitting form with with removed captcha field is no longer possible
1.3
- allow multiple forms on a single page (thanks to A. Grundner)
- small code improvements
1.2
- added: support for reCpatcha API v3 (default)
1.1.1
- fixed: script tag not shown on HTML forms
1.1
- removed option for V1
- added theme selection
- added size selection
1.0.1
- fixed: issue where check box doesn’t get recognized
1.0
- initial release