What This Is
This is a rule-based reasoning tool, not a monitoring or chaos-engineering product. It never contacts AWS, GCP, Azure, or any real system. Every dropdown you pick feeds a small set of independent reasoning modules — routing, data replication, compute, observability, and recovery — each of which writes a plain-English paragraph based on well-established multi-region architecture patterns. Nothing here is measured; it's reasoned through, the way an experienced architect would talk through a design on a whiteboard.
Why the Same Two or Three Combinations Keep Showing Up as Risky
Active-active topology with asynchronous replication during a network partition is the textbook split-brain setup — both regions individually think they're fine and keep accepting writes, and there's no consensus mechanism in the picture to stop them from disagreeing. Asynchronous replication, on its own, always carries some data-loss window, because writes are acknowledged before they're confirmed in the other region. These aren't edge cases the tool invented — they're the tradeoffs every multi-region design has to make explicitly, and the simulator's job is to surface them for the specific combination you picked rather than let them stay implicit.
Where This Fits Alongside a Real Failover Test
Use this before you design a game day, not instead of one — it's a fast way to sanity-check an architecture on paper, brief a team on what to expect, or spot a split-brain risk before it's built. It doesn't replace measuring actual DNS propagation in your account, actual replication lag under your write load, or actual autoscaling time for your cluster — those numbers only come from testing your real system.
Save and share your scenario as a permalink — coming soon