The chapter presents a new social media research tool for studying subreddits (i.e., groups) on Reddit called Communalytic. It is an easy-to-use, web-based tool that can collect, analyze and visualize publicly available data from Reddit. In addition to collecting data, Communalytic can assess the toxicity of Reddit posts and replies using a machine learning API. The resulting anti-social scores from the toxicity analysis are then added as weights to each tie in a “who replies to whom” communication network, allowing researchers to visually identify and study toxic exchanges happening within a subreddit. The chapter consists of two parts: first, it introduces our methodology and Communalytic’s main functionalities. Second, it presents a case study of a public subreddit called r/metacanada. This subreddit, popular among the Canadian alt-right, was selected due to its polarizing nature. The case study demonstrates how Communalytic can support researchers studying toxicity in online communities. Specifically, by having access to this additional layer of information about the nature of the communication ties among group members, we were able to provide a more nuanced description of the group dynamics.