Slack (https://slack.com) is a proprietary set of tools for team collaboration. It offers various integration with different services. We have a workspace at https://tjcsl.slack.com. The CSL's first widespread use of the Slack workspace began in August of 2018. Slack became the official form of communication under the direction of Omkar Kulkarni. It was replaced by Mattermost in December 2019 because Slack's free plan only allows for three months of message history and the school didn't want to pay for it.