Schema Registry

A schema registry is a central service that stores and versions the schemas for the messages flowing through your event streams or message queues. Producers register the schema of the events they emit; consumers fetch it to decode and validate what they receive. It's most associated with Kafka and formats like Avro, Protobuf, and JSON Schema. The problem it solves is coordinating change across decoupled services. In an event-driven system, the producer and consumer don't call each other directly — they're linked only by the message format. Without a registry, a producer that adds or renames a field can silently break every downstream consumer. A registry enforces compatibility rules (backward, forward, or full) so an incompatible schema change is rejected before it ships. For SaaS builders running any streaming or pub/sub architecture, a registry is how you evolve event schemas safely as the product grows. Practical note: choose a compatibility mode deliberately — backward compatibility (new consumers can read old data) is the common default — and treat schema changes with the same review rigor as a public API change.