The talk at the FOSDEM conference in 2023 was about the use of NetFlow in network analysis. The speaker, Alex, explained how NetFlow is used to extract information from IP packets and aggregate it into flows. He discussed the benefits of unsampled NetFlow for certain use cases, such as security and troubleshooting network problems. However, due to limitations in powerful networking gear, sampled NetFlow is now more commonly used. Alex then talked about how his organization, Switch, implemented unsampled NetFlow using a software implementation called SnapFlow. He described the hardware and software setup they used, including optical splitters, packet brokers, and white box switches. The speaker, Max, then discussed the architecture and scaling of SnapFlow, explaining how it is built using Snap, which is a networking application toolkit written in Lua. He highlighted the core values of Snap, which include simplicity, small size, and openness. Max also talked about the use of links to organize SnapFlow apps and mentioned the support for receive side scaling and software-based receive side scaling. He discussed the control plane and data plane segregation implemented in SnapFlow, as well as the use of libyang for configuration and application state management. Max also mentioned the flight recorder and UI provided with SnapFlow for profiling and analyzing performance. He concluded by mentioning the availability of commercial support for SnapFlow from Igalia. The talk ended with a Q&A session.