A package for capturing and analyzing network flow data and intraflow data, for network research, forensics, and security monitoring. Joy is a BSD-licensed libpcap-based software package for extracting data features from live network traffic or packet capture (pcap) files, using a flow-oriented model similar to that of IPFIX or Netflow, and then representing these data features in JSON. It also contains analysis tools that can be applied to these data files. Joy can be used to explore data at scale, especially security and threat-relevant data. JSON is used in order to make the output easily consumable by data analysis tools. While the JSON output files are somewhat verbose, they are reasonably small, and they respond well to compression. Joy can be configured to obtain intraflow data, that is, data and information about events that occur within a network flow, including: the sequence of lengths and arrival times of IP packets, up to some configurable number of packets. the empirical probabilit