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MessagePack ↔ JSON Converter / Viewer

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What is MessagePack ↔ JSON Converter / Viewer?

This tool converts JSON to MessagePack and decodes MessagePack back to JSON.

It is useful for APIs, binary payload inspection, backend debugging, compact serialization formats, and interoperability testing.

How to use MessagePack ↔ JSON Converter / Viewer

  1. Paste JSON and click JSON → MessagePack to encode it.
  2. Paste Base64-encoded MessagePack and click MessagePack → JSON to decode it.
  3. Inspect the hex output and byte size.
  4. Copy JSON, Base64 MessagePack, or hex output if needed.

Tips

  • MessagePack is a binary format, so this tool uses Base64 for safe text input and output.
  • Hex output is useful for debugging payloads and comparing binary data.
  • If decoding fails, make sure the input is valid Base64-encoded MessagePack.
  • This tool is useful when testing APIs or backend serializers.

MessagePack and JSON checks before compacting API payloads

MessagePack reduces payload size while retaining structure, but extension types, map keys, numeric precision, and client support can differ.

Verify extension types

Document any ext values, timestamps, binary blobs, and custom encodings so consumers can decode them consistently.

Protect numeric values

Check large integers, decimals, counters, and money-like values before JavaScript or another runtime coerces precision.

Check map keys

Confirm whether your clients expect string keys only or can safely handle integer, binary, or mixed MessagePack map keys.

Test round trips

Encode and decode real samples with each target SDK before replacing JSON in APIs, queues, or cached objects.

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MessagePack ↔ JSON FAQ

Why does MessagePack use Base64 here?
Because MessagePack is binary, Base64 makes it easier to paste and copy safely in a text UI.
Can this tool decode MessagePack to JSON?
Yes. Paste Base64-encoded MessagePack and it will decode it into formatted JSON.
Can it encode JSON to MessagePack?
Yes. Paste JSON and the tool will return Base64 and hex representations of the MessagePack payload.
Is my MessagePack data stored?
The payload is sent to the Toolinix server for the current conversion. It is filtered from application logs and is not intentionally retained after the response is returned.