From 2019 to 2022 I had the pleasure of working on Airy, an “Open Source App Framework to build streaming apps with real-time data.” [sic]. At its core Airy is a cluster of Kafka Streams applications and frontends that allow you to connect to messaging sources (e.g. Slack, Facebook, Twitter, etc.) and build streaming applications on top of them.
This is a small project that I started in 2021 to make the data from the International Energy Agency (IEA) freely available to everyone. You can read more about the motivation behind it in this thread: https://twitter.com/chrismatisch/status/1459872989751787521