This specification describes technologies relating to launching applications from content items in webpages. In general, one aspect of the subject matter described in this specification can be embodied in methods that include receiving a content item including a first data element that identifies an application and a second data element that identifies a product. The methods may further include displaying the content item, receiving a user selection of the content item, and, in response, automatically checking if the application is installed on a user device. The methods may further include transmitting a request, including the first data element, to a server and installing the application identified by the first data element on the user device. The methods may further include launching the application with the second data element as an input so that the first content displayed by the application relates to the product.