Format:
Payload
Decoded Output
Click Decode to parse the payload.
Decode Kafka messages — JSON, Base64, Hex, and Avro wire format
Paste a raw Kafka message and decode it as JSON, Base64, Hex, or Confluent Avro wire format. Extract the schema ID from the magic-byte header and inspect payload structure — locally, with no broker connection needed.
Frequently Asked Questions
- What is the Confluent Avro wire format?
- Messages serialized with Confluent Schema Registry start with a magic byte (0) followed by a 4-byte schema ID, then the Avro-encoded payload. This tool extracts the schema ID for you.
- Why does my Kafka message look like garbage text?
- It is likely binary-encoded (Avro, Protobuf) rather than plain JSON. Try the Avro wire-format or Hex decoding modes to reveal the structure, and check the first bytes for a schema ID header.
- How do I find which schema a message used?
- Decode the wire-format header to get the schema ID, then look it up in your Schema Registry at /schemas/ids/<id>.
- Is my message content sent anywhere?
- No — decoding happens in your browser, which matters because Kafka messages often contain production data.