Protocols & Binary Serialization
Paste hex, Base64 or decimal bytes, or open a local binary file. Switch direction to encode standard JSON.
Bytes and files are processed in this browser; nothing is uploaded.
Paste bytes or open a file to inspect one MessagePack value.
A cache record or network frame can contain valid MessagePack yet look like unreadable noise. This MessagePack decoder shows its nested values and their wire types before you copy a JSON preview.
A plain MsgPack to JSON conversion may hide the difference between text and binary, round a 64-bit identifier, or ignore bytes after the first object. Here the tree keeps those distinctions visible, while JSON to MessagePack is available for checking a normal JSON sample.
The wire types remain visible even when JSON cannot express them.
The MessagePack decoder labels strings, raw bin bytes, extension codes and exact 64-bit integers separately. A JSON preview adds explicit markers where JSON has no equivalent type, so inspection does not quietly erase the clue you needed.
A complete first object followed by extra bytes is reported at the first trailing byte. Truncated payloads also report their byte offset. You can tell a concatenated stream or damaged capture from a clean single value.
Hex is the default. Change to Base64 or decimal bytes before pasting another representation; the tool does not guess an ambiguous short string. A local file is read as raw bytes and switches to decode mode.
Auto-process waits 350 ms after input changes. Switch it off to show the Decode or Encode button and use Ctrl/Cmd+Enter. Editing input or its format immediately disables export of the old result.
Read node types and byte offsets in the tree, then use the JSON preview for downstream reading. Encode mode can download actual .msgpack bytes rather than just a printed hex string.
Expand keys and indices in a typed tree. Nodes show their starting byte offset and encoded length, and large structures appear 100 visible rows at a time.
Raw bin values remain hex bytes. Unknown ext values retain their signed type code and full payload; the standard timestamp extension also shows seconds, nanoseconds and raw bytes.
Switch to JSON to MessagePack for ordinary JSON values. Copy hex, Base64 or decimal bytes, or download the true binary file for another decoder or application.
Paste hex, Base64 or a comma-separated decimal byte array, selecting the matching format first. You can also open a local binary file; it is read as bytes, not as UTF-8 text.
The tree distinguishes bin from str. Unknown ext values show their signed type code and raw hex payload. The JSON preview uses explicit markers because normal JSON cannot represent either wire type directly.
Yes in the tree. Values outside JavaScript's safe integer range are kept as exact decimal strings in marked JSON preview objects, never silently rounded to a Number.
One MessagePack value finished before the input ended. The error gives the first extra byte offset; the rest may be a second message, a framing byte or damaged capture.
No. Pasted text and selected files are parsed in your browser. File reading uses the local File API; this page does not send the payload to a server.
Still have a question?
Load the example to compare the typed tree with its JSON preview, then inspect your own payload or encode a standard JSON sample with this MessagePack decoder.
Runs locally in your browser.