Distributed Systems2026.038 min
The log is the truth
Ten services, no shared database, and one append-only record everyone agrees on. Notes on designing an event log you can actually reason about.
Distributed systems become difficult to reason about when every service keeps its own version of what happened.
An append-only event log gives the system a shared history — a record that services can consume, replay, and reason about independently.
One record. Many consumers.
The interesting part isn't simply storing events. It's deciding what belongs in the log, what guarantees consumers can rely on, and how the system behaves when something goes wrong.