We are a small team working on something of moderate complexity.<p>We don&#x27;t do a lot of request&#x2F;response and most of our services interoperate asynchronously. The overall system is eventually consistent and we keep close tabs on the latency for changes propagating through the system. Different pieces have different latency requirements.<p>We don&#x27;t have any services that exist solely to wrap a database -- in fact, most services read directly from databases. Updating them, however, is done by a single service.<p>We use S3 and Kafka as coordination points for large amounts of data.<p>We use DNS for service discovery.<p>Most information flows unidirectionally through the system. This + async everywhere means no race conditions.<p>The format of messages between systems changes very, very rarely. This is largely in part due to how we have segmented functionality -- most of the time, services just need to inform another service that some change or event has happened -- then the service itself contains all of the logic for what that means.