Avro to JSON Converter

Generate sample JSON from an Avro schema (.avsc). Runs locally in your browser.

Avro Schema

JSON Output

{
  "orderId": "orderId-1",
  "customer": {
    "name": "name-1",
    "email": "[email protected]"
  },
  "items": [
    {
      "sku": "sku-1",
      "quantity": 1,
      "unitPriceCents": 1
    }
  ],
  "status": "PAID"
}

The Kafka IDE

Mock and produce Avro messages in Kafma

Kafma is a desktop app for Kafka. Generate sample JSON from your Schema Registry with registered references resolved, then edit, validate, and produce Avro messages to a topic.

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Kafma generating sample JSON from the OrderCreated Avro schema in the Schema Registry Mock tab
Kafka Schema Explorer

Avro to JSON FAQ

Why is a union wrapped like {"string": "note-1"} in Avro JSON?
Avro JSON encoding wraps non-null union values in the branch type name. null stays JSON null. See the Avro JSON encoding
Why is timestamp-millis a large number in Avro JSON?
timestamp-millis is encoded as milliseconds since the Unix epoch, using a JSON number. It is not an RFC 3339 string. See the Avro JSON encoding
Can Avro long values lose precision in JSON?
Avro long values are JSON numbers. JavaScript cannot represent every integer outside its safe range exactly. Use a parser that preserves large integers; quoting a value changes its JSON type and does not match an Avro long schema.
Why is a referenced Avro type unknown?
This tool does not fetch other files or Schema Registry subjects. Include the referenced named type definitions in the pasted JSON Avro schema (.avsc).
Why does generation fail for deeply nested schemas?
This tool limits nesting to 4 levels. A nullable union can fall back to null, but a required record beyond the limit causes generation to fail. Try a smaller schema to preview the structure.
Can I send this JSON directly as an Avro Kafka message?
The JSON uses Avro JSON encoding. Producing a binary Avro message requires the matching schema and a serializer. In Kafma, select the schema in Kafka Console, generate or edit a payload, then produce it.
Can I decode binary Avro to JSON?
No. This page generates sample JSON from an Avro schema. It does not decode binary Avro payloads. To read live Kafka messages, use Kafka Console.
Is my input uploaded?
No. Conversion runs in your browser. Your input and generated output are not uploaded.
Can I generate an Avro schema from sample JSON?
Use the JSON to Avro converter to infer an Avro schema from sample JSON.