MessagePack to JSON Converter
Decode a single MessagePack value into JSON with explicit representations for binary data, timestamps and large integers.
Your input is sent to this site only after you choose Convert on server. The conversion runs for this request and no history is saved. Upload up to 4 MiB combined; Office files have a 2 MiB limit.
Choose your file
Choose a file or load the example to see how the converter works.
How to use MessagePack to JSON Converter
- Load the example or paste your own input.
- Review the settings, then select Convert on server to send input for processing.
- Review the result, then copy or download it.
What this tool helps you do
Inspect a MessagePack export without manually reading binary tags. Upload one binary value and download formatted JSON. JSON-compatible numbers, strings, arrays and maps retain their values. Binary byte arrays become objects containing Base64 text; timestamps and integers that JSON cannot represent exactly use explicit tagged representations so those distinctions are visible.
Format rules and limitations
The input must contain exactly one complete MessagePack value. Non-string map keys, unsafe object keys, unsupported extension types and oversized containers are rejected. A decoded binary wrapper is a report representation and is not automatically interpreted as binary by the separate JSON encoder. Upload and output limits apply independently, so Base64 expansion can make a result too large. This does not decompress a surrounding archive or guess a framing protocol.
What should I check before relying on the output?
The input must contain exactly one complete MessagePack value.
Is input uploaded?
This tool sends input to this site’s conversion API after you select Convert on server. Files use bounded workers and, when needed, private temporary folders deleted after processing or cancellation. No conversion history is saved. The converter does not upload files to a third-party conversion service.