Getting the feeling Segment didn't really stop using microservices.

Sounds like they just redrew their service boundary, from Integration APIs to Business Function.

Centrifuge sounds like a new service deals with connecting to integration APIs, so they've replaced 140+ services with one.

Another service they've spun up is Traffic Recorder, and its responsibility is to eliminate the need for http requests when testing integrations.

Feels like the biggest change is going from so many repos to a monorepo.