Hey, glad you liked it!

Is it doing http calls every time a switch conditional is hit?

No. This would result in acceptable latency and performance degradation, because one page render can include many such conditionals. The intent is to improve the customer experience. Perceptibly slowing down the product would be unacceptable.

How are all the services accessing this central circuit breaker?

In effect, they are not (in an active sense). Each service pushes event logs to a central system. If the events indicate a degradation, the central system pushes back state changes (e.g. turning off the conditional) to local caches on each service.

Does the circuit breaker have a binary state (on or off)?

Yes … ish. The Circuit Breaker doesn’t really have state, each feature toggle does. The platform at large supports more granular control of these toggles, but the Circuit Breaker will only set a feature toggle to “off” in case of a problem. In that sense, the effects of the Circuit Breaker are binary.

Hope that helps.