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Adds CAPTCHA anti-spam methods to WordPress on the forms for comments, registration, lost password, login, or all.

Spammers have been able to bypass my CAPTCHA, what can I do?

First check this: make sure the only other security plugins you have are Akismet or WP-spamFree. Akismet and WP-spamFree are the only other anti-spam plugins approved for use with SI CAPTCHA Anti-Spam, others can simply break the CAPTCHA validation so that the CAPTCHA is never checked. If another security plugin is combined(not Akismet or WP-spamFree), the captcha may not block invalid code! Be sure to always test all the CAPTCHA forms after installing or updating themes or plugins.

Sometimes your site becomes targeted by a spammer that uses a combination of a bot and human captcha solver. See this help forum for a solution

Try enabling the setting "Enable honeypot spambot trap" on the plugin settings page.

Try allowing only Registered users to post, and or moderating comments. Read more about Combating Comment Spam

How can I change the color of the CAPTCHA input field on the comment form?

If you need to learn how to adjust the captcha input form colors, See this FAQ

Troubleshooting if the CAPTCHA form fields and image is not being shown:

Do this as a test: Activate the SI CAPTCHA plugin. In Admin, click on Appearance, Themes. Temporarily change your theme to the "WordPress Default" theme (default for WP2), or "Twenty Ten" (default for WP3). It does not cause any harm to temporarily change the theme and change back. Does it work properly now? If it does then the theme you are using is the cause.

Missing CAPTCHA image and input field on comment form? You may have a theme that has a not properly coded comments.php

When diagnosing missing CAPTCHA field on comment form.... The version of WP makes a difference...

(WP2 series) Your theme must have a <?php do_action('comment_form', $post->ID); ?> tag inside your /wp-content/themes/[your_theme]/comments.php file. Most WP2 themes already do. The best place to locate the tag is before the comment textarea, you may want to move it up if it is below the comment textarea.

(WP3 series) Since WP3 there is new function comment_form inside /wp-includes/comment-template.php. Your is theme probably not up to current code to call that function from inside comments.php. WP3 theme does not need the do_action('comment_form'... code line inside /wp-content/themes/[your_theme]/comments.php. Instead, it uses a new function call inside comments.php: <?php comment_form(); ?> If you have WP3 and still have the missing captcha, make sure your theme has <?php comment_form(); ?> inside /wp-content/themes/[your_theme]/comments.php. (look inside the Twenty Ten theme's comments.php for proper example)

Troubleshooting if the CAPTCHA image itself is not being shown:

By default, the admin will not see the CAPTCHA. If you click "log out", go look and it will be there.

If the image is broken and you have the CAPTCHA entry box:

This can happen if a server has folder permission problem, or the WordPress address (URL) or Blog address (URL) are set incorrectly in WP settings: Admin, Settings, General

See FAQ page on fixing this problem

Sometimes the captcha image and captcha input field are displayed AFTER the submit button on the WP2 comment form.

WP2.0 themes must have a <?php do_action('comment_form', $post->ID); ?> tag inside the /wp-content/themes/[your_theme]/comments.php file. Most WP2 themes do. The best place to locate the tag is before the comment textarea, you may want to move it if it is below the comment textarea. This tag is exactly where the captcha image and captcha code entry will display on the form, so move the line to before the comment textarea, uncheck the 'Comment Form Rearrange' box on the 'Captcha options' page, and the problem should be fixed. (WP3 with a WP3 proper theme will not have this problem)

Alternate Fix for the captcha image display order

You can just check the 'Comment Form Rearrange' box on the admin plugins 'Captcha options' page and javascript will attempt to rearrange it for you. Editing the comments.php, moving the tag, and uncheck the 'Comment Form Rearrange' box on the 'SI Captcha options' page is the best solution.(WP3 with a WP3 theme will not have this problem)

Why is it better to uncheck the 'Comment Form Rearrange' box and move the tag?

Because the XHTML will no longer validate if it is checked.

The CAPTCHA refresh button does not work

Your theme could be missing the wp_footer PHP tag. Your theme should be considered broken if the wp_footer PHP tag is missing.

All WordPress themes should always have <?php wp_footer(); ?> PHP tag just before the closing </body> tag of your theme's footer.php, or you will break many plugins which generally use this hook to reference JavaScript files. The solution: edit your theme's footer.php and make sure this tag is there. If it is missing, add it. Next, be sure to test that the CAPTCHA refresh button works, if it does not work and you have performed this step correctly, you could have some other cause.

The CAPTCHA is not working and I cannot login at my login page

This failure could have been caused by another plugin conflict with this one. If you use CAPTCHA on the login form and ever get locked out due to CAPTCHA is broken, here is how to get back in: FTP to your WordPress directory /wp-content/plugins/ Delete this folder:


This manually removes the plugin so you should be able to login again.

Is this plugin available in other languages?

Yes. To use a translated version, you need to obtain or make the language file for it. At this point it would be useful to read Installing WordPress in Your Language from the Codex. You will need an .mo file for this plugin that corresponds with the "WPLANG" setting in your wp-config.php file. Translations are listed below -- if a translation for your language is available, all you need to do is place it in the /wp-content/plugins/si-captcha-for-wordpress/languages directory of your WordPress installation. If one is not available, and you also speak good English, please consider doing a translation yourself (see the next question).

The following translations are included:


  • Albanian (sq_AL) - Romeo Shuka
  • Arabic (ar) - Amine Roukh
  • Belorussian (by_BY) - Marcis Gasuns
  • Chinese (zh_CN) - Awu
  • Czech (cs_CZ) - Radovan
  • Danish (da_DK) - Parry
  • Dutch (nl_NL) - Robert Jan Lamers
  • French (fr_FR) - Pierre Sudarovich
  • German (de_DE) - Sebastian Kreideweiss
  • Greek (el) - Ioannis
  • Hungarian (hu_HU) - Vil
  • Indonesian (id_ID) - Masino Sinaga
  • Italian (it_IT) - Gianni Diurno
  • Japanese (ja) - Chestnut
  • Lithuanian (lt_LT) - Vincent G
  • Norwegian (nb_NO) - Roger Sylte
  • Polish (pl_PL) - Tomasz
  • Portuguese Brazil (pt_BR) - Newton Dan Faoro
  • Portuguese Portugal (pt_PT) - PL Monteiro
  • Romanian (ro_RO) - Laszlo SZOKE
  • Russian (ru_RU) - Neponyatka
  • Serbian (sr_SR) - Milan Dinic
  • Slovakian (sk_SK) - Marek Chochol
  • Spanish (en_ES) - zinedine
  • Swedish (sv_SE) - Benct
  • Traditional Chinese, Taiwan Language (zh_TW) - Cjh
  • Turkish (tr_TR) - Burak Yavuz
  • More are needed... Please help translate.

Can I provide a new translation?

Yes please. Please read How to translate SI Captcha Anti-Spam for WordPress

Can I update a translation?

Yes please. Please read How to update a translation of SI Captcha Anti-Spam for WordPress

Requires: 3.0 or higher
Compatible up to: 4.7.1
Last Updated: 2 days ago
Active Installs: 300,000+


4.1 out of 5 stars


0 of 5 support threads in the last two months have been marked resolved.

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