An electronic device displays a messaging user interface of a messaging application on the display, the messaging user interface including a conversation transcript of a messaging session between a user of the electronic device and at least one other user, a message-input area, and an icon for an interactive application that is displayed within the conversation transcript. While displaying the messaging user interface, the device detects an input that activates the icon for the interactive application; in response to detecting the input that activates the icon for the interactive application, the device displays a user interface for the interactive application in a first state. While displaying the user interface for the interactive application, the device detects a first user input within the user interface for the interactive application; and, in response to detecting the first user input within the user interface for the interactive application: the device changes display of the user interface for the interactive application from the first state to a second state, and sends information, to the one or more electronic devices that correspond to the at least one other user included in the messaging session, indicating that the first user input was made in the user interface for the interactive application, wherein the one or more electronic devices display an indicia of the first user input.