MessagePack converter

MessagePack is a binary serialization format that represents the same data as JSON, such as maps, arrays, strings, numbers, booleans and null, but in fewer bytes and faster to parse. It is used by Redis Lua scripts, Fluentd log shipping, SignalR, Neovim RPC and many microservice protocols. This converter encodes JSON to MessagePack hex and decodes hex back to JSON for inspection and debugging.

How to use it

1. Paste JSON to encode it into MessagePack bytes shown as hex.
2. Or paste MessagePack hex to decode it into readable JSON.

Example

The JSON object with key compact set to true and key schema set to 0 encodes to:

82 A7 63 6F 6D 70 61 63 74 C3 A6 73 63 68 65 6D 61 00

That is 18 bytes instead of 27 bytes of JSON text. 82 means a map with 2 entries, A7 a 7-byte string, C3 is true and 00 is the positive integer 0.

Format basics

• fixint: integers 0 to 127 fit in one byte.
• fixstr: strings up to 31 bytes use a single header byte (0xA0 to 0xBF).
• fixmap and fixarray: small maps and arrays use one header byte (0x80 and 0x90 ranges).
• Larger values use type bytes followed by explicit lengths.
• bin and ext types store raw bytes and custom types such as timestamps.

When to choose MessagePack

It is a good fit for high-volume internal traffic where bandwidth and parse time matter. For public APIs, JSON remains easier to debug and universally supported. Compared with Protocol Buffers, MessagePack needs no schema, which is convenient but means no compile-time type checking.