Exploratory testing is an important activity for improving software quality. Nonetheless, few studies have been conducted to support exploratory testing. One reason for this is the lack of available data on exploratory testing activities. We propose LatteArt, a tool to assist developers in recording, visualizing, and managing exploratory testing activities. LatteArt has a rich user interface and a variety of features to support exploratory testing and is publicly available. We conducted a questionnaire with three developers to assess whether LatteArt addresses the challenges of exploratory testing. In our questionnaire, two or more developers indicated that LatteArt contributes to overcoming 14 of the 17 weaknesses in exploratory testing that were stated in the existing literature. Recorded test activity data via LatteArt can be easily accessed using REST APIs, which enables researchers to utilize the data and facilitate exploratory testing research. A video of the tool demo can be found at the URL: https://www.youtube.com/watch?v=_lfaRN8ipA4