Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing user interface development tools. In one aspect, a method includes receiving console logs that specify sequences of user interface events that occurred during user sessions. For each of multiple user sessions, a received console log for the user interface events that occurred during that user session is identified. Playback data that presents visual changes of one or more user interfaces of the publisher that occurred during that user session is generated. An interactive interface is generated and provided. The interface includes session replay area in which the playback data presents the visual changes of the one or more user interfaces of the publisher that occurred during that user session and a console log area that presents console entries from the console log for the user interface events that occurred during that user session.