JSON → Apache Avro schema

Client

Paste JSON to emit an Avro schema as JSON—nested objects become inline record types; arrays use the first element to guess item shape. Refine numeric types and nullability before registering or generating code.

Learn more: Apache Avro from JSON

Emit a single Avro schema as JSON—usually a record with snake_case field names, or an array type when the root JSON is an array. Nested JSON objects become inline record definitions.

Types and nullability

JSON numbers map to double in this draft; Avro often uses int, long, float, or fixed for real pipelines—edit after you know the domain. Missing keys and true optionality are not inferred from one sample; model them with unions such as ["null", "string"] or explicit defaults in your tooling.

Compared to Protocol Buffers

Both describe structured payloads; Avro schemas are JSON documents commonly used with Kafka and Schema Registry, while .proto files target protobuf and often gRPC. Use both tools when comparing wire formats for the same sample data.

JSON → Avro

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Parses JSON in your browser and emits classes inferred from the sample shape. Nested objects become nested types; arrays use the first element only to guess item shape. Nothing is uploaded.

Output is Avro schema as JSON—paste into Schema Registry or codegen after review. JSON numbers map to double; switch to int or long when values are integer-only. Use unions such as ["null", "string"] for optional fields; this draft does not infer optionality from a single sample.

Common use cases

  • Sketch a record schema before registering a subject in Confluent or another Schema Registry.
  • Compare snake_case Avro field names with camelCase keys from upstream JSON APIs.

Common mistakes to avoid

  • Treating one sample as the full contract

    Optional keys and unions are not inferred—add ["null", T] or enums after you know the real API.

FAQ

Is generation local?

Yes. Output is produced entirely in your browser.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • json to avro schema
  • sample json to avro record

More tools

Related utilities you can open in another tab—mostly client-side.