How to open a .msgpack file (Windows, Mac, Linux)

Q: Why can't I open my .msgpack file?

Usually your computer lacks an app that understands MessagePack. Install one of the apps listed here, or convert the file to a more common format.

A .msgpack file is a MessagePack Serialized Data. If double-clicking does nothing, your computer simply does not have an app that reads MessagePack yet. Here is how to fix that on each operating system, using free software wherever possible.

Open a .msgpack file step by step

Confirm the file really is a .msgpack. Drop it into the WhatFileType file identifier, which reads its signature without uploading anything.
On Windows, open it with Python (msgpack) or Node.js (@msgpack/msgpack).
On Mac, use Python (msgpack) or msgpack-tools (CLI).
On Linux, try Python (msgpack) or msgpack-tools (CLI).
Still stuck? Convert the .msgpack to json, which opens more widely.

Best apps to open .msgpack files

Windows

Python (msgpack)
Node.js (@msgpack/msgpack)
msgpack-tools (CLI)

macOS

Python (msgpack)
msgpack-tools (CLI)

Linux

Python (msgpack)
msgpack-tools (CLI)

Before you open it: Safe as data. Like all deserialization, decoding untrusted input deserves care: use a maintained library and avoid application-level types that auto-instantiate objects.

Frequently asked questions

Why can't I open my .msgpack file?

Almost always because no installed app understands MessagePack. Install one of the apps above, or convert the file to a format your existing software already reads.

How do I read a .msgpack file?

Decode it with a MessagePack library, for example msgpack.unpack() in Python, or convert it to readable JSON with the msgpack2json tool from msgpack-tools.

What is the difference between MessagePack and JSON?

The data model is nearly identical; the encoding is not. MessagePack is binary, smaller and faster to parse, while JSON is human-readable text.