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WordPress Anti-spam plugin

Why humans should prove that they are humans by filling captchas? Lets bots prove that they are not bots with adding javascript to their user-agents!

Anti-spam plugin blocks spam in comments automatically, invisibly for users and for admins.

  • no captcha, because spam is not users' problem
  • no moderation queues, because spam is not administrators' problem
  • no options, because it is great to forget about spam completely

Plugin is easy to use: just install it and it just works.

How does Anti-spam plugin work ?

The blocking algorithm is based on 2 methods: 'invisible js-captcha' and 'invisible input trap'.
The 'invisible js-captcha' method is based on fact that bots does not have javascript on their user-agents.
The 'invisible input trap' method is based on fact that almost all the bots will fill inputs with name 'email' or 'url'.

How does Anti-spam plugin work in details?

Two extra hidden fields are added to comments form. First field is the question about the current year. Second field should be empty.
If the user visits site, than first field is answered automatically with javascript, second field left blank and both fields are hidden by javascript and css and invisible for the user.
If the spammer tries to submit comment form, he will make a mistake with answer on first field or tries to submit an empty field and spam comment will be automatically rejected.

How to test what spam comments are rejected?

You may enable sending all rejected spam comments to admin email.
You should edit "anti-spam.php" file and find "$antispam_send_spam_comment_to_admin" and make it "true".

What is the percentage of spam blocked?

Anti-spam plugin blocks about 99.9% of automatic spam messages (sent by spam-bots via post requests).
But Anti-spam plugin will pass the messages which were submitted by spammers manually via browser. But such messages happens very rarely.

Not enough information about the plugin?

You may check out the source code of the plugin.
The plugin has about 100 lines of code and pretty easy to read. I was trying my best to make plugin's code clean.
Plugin is small but it makes all the dirty work against spam pretty good. You may give it a try.

How to reduce the amount of spam?

Do not order spam-newsletters because people hate spam and people will not like products received from spam. Do not order products from spam. If spam will be less effective than spammers will stop sending it.


What I know now about spam and spam-bots?

  • All spam-bots does not have javascript
  • Spam-bots submit all inputs from forms so forms are parsed before being submitted
  • If input have 'email' in its name than many spam-bots tries to submit email in it automatically
  • All spam-bots does not have Cookies (Cookie array is empty)
  • Spam is very complicated now, pretty "smart" and fully automated

97 comments on “Anti-spam

  1. I like this plugin BUT have a problem with it, and am hoping you have a solution for me. If a person comments on my site who has NO gravatar, the gravatar of one of my other commenters is being used. How can this be fixed? What do I need to do to fix this? Please email me and let me know. Thanks!

  2. Does the Anti-Spam plugin block valid comments?

    Since installing the plugin I have received zero comments.There are hits on the comments page but they never appear.on the blog. I tested it an was able to submit a comment myself (while logged off from the website).

    Disabling the plugin results in a flood of comments. Enabling the plugin results in no (zero) comments at all.

    • webvitaly Post author

      Anti-spam plugin does not block valid comments.
      Anti-spam plugin works on your correctly.
      I submitted test comment and it worked great.
      Probably your site is not popular enough.
      Less than 0.5% of the visitors leave comments.

      P.S. You disabled right click on your site and you killed mine few extra minutes and made me mad while I was investigating your site.
      If you think that this plugin will protect your site from copying info - than you are wrong.
      If somebody will want to copy information - he will definitely do it but with much effort and bad mood.
      Wikipedia does not disable right click on their site, and many people copy its content and share it and Wikipedia gets more popularity from it - think about it.
      Just delete this plugin and ask people (somewhere on your site) to add a backlink to your site when copying information and this approach works great in the internet.

  3. Seems to work pretty well.

    Is it possible to have anything questionable be moved to the spam filter rather than just delete? I would like to see if there are any false-positives.

  4. The plugin seems to be working well, but all entered comments Are Converted To Title Case Like This. I'm not sure why, given that I know they aren't being entered that way (tested with my own comments).

    Any idea how to fix this?


    • webvitaly Post author

      This problem is not related to Anti-spam plugin.
      Probably it is caused by some other plugin you installed.

      • My blog is brand new and I had only you, a 'floating icons' one, and a 'sidebar widget' one. It was the sidebar thing. Removed and things look right now. Thanks for the quick reply!

  5. Pingback: Best WordPress Comment Spam Plugin -

  6. I used to battle with 50 spammy comments every day. Since i installed your plugin spam comments disappeared.
    Great tool. Really works



  7. Thanks for sharing this plugins with us. I am really helpful to you. Next time I will try to donate some amount for you.

  8. Pingback: How to stop spam on your self-hosted blog or website

  9. Pingback: Chris' Blog » Blog Archive » WordPress Spam

  10. I used to get at least 10 spam comments a day, every day.. despite have two "simple" anti-spam measures (an "are you human check box and a mathmatical challenge question). I hate these stupid questions because the commenters have to deal with them! Anyway, I installed Anti-spam, and IMMEDIATELY saw improvement. Not a single spam comment so far, and I was able to remove all my other anti-spam plugins. Great tool!

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