Schema Registry
A central store of the schemas for messages in a streaming system, enforcing compatibility as producers and consumers evolve.
A schema registry is a central service that stores and versions the schemas (Avro, Protobuf, JSON Schema) for the messages flowing through a streaming platform like Kafka. Producers register a schema and consumers fetch it, so both sides agree on the shape of the data and it can evolve safely.
Worked example: a producer adds an optional field and registers a new schema version; the registry checks it is backward-compatible before allowing it, so existing consumers keep working while new ones use the added field. Gotcha: the registry’s value is the compatibility CHECK it enforces (backward, forward, or full) — skip it and a producer’s schema change silently breaks every consumer downstream; the registry turns “schema change” from a coordinated outage into a safe, gated operation.