Techniques for in-line filtering of insecure or unwanted mobile components or communications (e.g., insecure or unwanted behaviors associated with applications for mobile devices (“apps”), updates for apps, communications to/from apps, operating system components/updates for mobile devices, etc.) for mobile devices are disclosed. In some embodiments, in-line filtering of apps for mobile devices includes intercepting a request for downloading an application to a mobile device; and modifying a response to the request for downloading the application to the mobile device. In some embodiments, the response includes a notification that the application cannot be downloaded due to an application risk policy violation.