Placing a CAPTCHA,

How would I go about placing a captcha in my application?
I know google has the service, but how could I integrate it to my app?


Unfortunately, it’s hard to suggest a certain solution without a detailed description of your task.

As a starting point, I would recommend taking a look at this Vaadin Add-on and our documentation regarding how it can be integrated into the CUBA App.


thank you for constantly responding,

we have a public page, which has a form on it. and we wish to keep it spam free.

I am having trouble bringing in the add on you suggested because we are only using Gradle, ant the site has only a Maven Access.

Any maven dependency definition can be easily converted to gradle, e.g.:


equals to


If you’re using bintray repository, you’ll need to add vaadin-addons in order to download addon jars.

Similar to dependencies, maven repository definition can be converted to gradle:


equals to

maven {
    url ''


@arturoams were you able to use the suggested vaadin add-on and integrate it?

I’ve tried following the instructions provided above on how to integrate the Vaadin Recaptcha addon to my Cuba application, and i get this error.

Loading inherited module 'lu.balouic.kader.femata.web.toolkit.ui.AppWidgetSet'
   Loading inherited module 'com.wcs.wcslib.vaadin.widget.recaptcha.ReCaptcha'
      [ERROR] Unable to find 'com/wcs/wcslib/vaadin/widget/recaptcha/ReCaptcha.gwt.xml' on your classpath; could be a typo, or maybe you forgot to include a classpath entry for source?

Any idea what i could be doing wrong?


It seems that you’ve added widgetset dependency for this addon, but it has no widgetset, so removing com.wcs.wcslib.vaadin.widget.recaptcha.ReCaptcha from tour AppWidgetSet.gwt.xml should help.