Event Store is an ACID-compliant stream database with just 24 bytes of mutable state. It is also open source on GitHub and largely written in managed code, making it an excellent code base to start investigating database internals. In this session we'll take a deep dive into the SEDA architecture of Event Store, from the client protocol down to the storage engine and replication model, We'll discuss some of the hard decisions and why we made them, and discuss some of the tradeoffs which must be considered when building large scale systems on a managed platform.