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JSON to Avro Schema

Generate Apache Avro schemas from JSON. Records, unions for optional fields, arrays, and logical type hints are inferred from your sample.

JSON input

Paste JSON, optionally name the root type, then generate.

Your Avro schema code will appear here.
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Schemas for streaming data

Kafka producers and consumers agree on shape through Avro schemas. This generator converts a sample event payload into a registry ready schema, so your topics get type safety without hand writing JSON schema documents.

Unions capture real world messiness

Event data is rarely uniform. By turning nulls and missing keys into null unions with defaults, the generated schema tolerates the variance your sample already proved exists.

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JSON to Avro Schema FAQs

What is Avro used for?
Avro is a compact binary serialization format common in Kafka pipelines and Hadoop. Schemas defined in JSON describe the data so producers and consumers stay in sync.
How are optional fields expressed?
Fields that were null or missing become unions like ["null", "string"] with a null default, which is the Avro idiom for optional data.
How are nested objects handled?
Each nested object becomes its own named record type, which Avro requires for structured data inside a schema.
What about arrays?
JSON arrays become Avro arrays with an inferred items type, including arrays of nested records for lists of objects.
Can I use this with a schema registry?
Yes. The output is a standard Avro schema JSON document, ready to register with Confluent or Apicurio schema registries.
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