Over the last two months, Mathspace's feature flag system evaluated 6.6 billion flags, averaging 110 million flag decisions per day. The two request-path lookups needed for those decisions, fetching user attributes and loading the compiled rule config, stayed around 40 ms at the 99.5th percentile.

We thought the hard part of going multi-region would be standing up another copy of the application. It was actually preserving the simple user experience of one public domain while keeping region-specific data and operational behavior from bleeding across boundaries. Mathspace had a monolith that was becoming two

What if we could also skip the creation part and create instances on the fly when the client first connected? This was the light bulb moment!