Intended for use by children, KidRex is a content-sensitive search engine by Google. The search engine filters out inappropriate content for children and emphasizes kid-related content when displaying search results. The service is free to use and also offers tips for parents to help them ensure that their children only have access to appropriate content.

In addition to the filter algorithms of Google SafeSearch, KidRex has its own database of websites that it does not list in search results. Likewise, the search engine displays an error page when the user puts inappropriate words into the search box. Google claims to test the service daily to make sure it remains up to date.

Google warns that KidRex may fail to filter out some inappropriate content. In such cases, parents can fill out a Web page removal request form to make sure that Google adds the inappropriate Web page to its list of blocked URLs. The form requires the address of the page and the search terms used to find it.

KidRex suggests that parents keep computers in a central place to ensure that the parents are able to see the children's online activities. It also warns that kids may come in contact with strangers online and suggests that parents should teach their children about the dangers related to meeting up with strangers or giving out personal information. Parents can also check the browser histories on computers used by their children to make sure they are not viewing inappropriate content.