---
id: u-msgpack-python
version: "2.8.0"
license: MIT
license_treatment: permissive
maintenance: active
---

# u-msgpack-python — A portable, lightweight MessagePack serializer and deserializer written in pure Python.

License: permissive · Maintenance: active · Downloads: 1.8M/mo

## What it is and what it does

u-msgpack-python is a pure-Python implementation of the MessagePack serialization format. It encodes Python objects into a compact binary representation and decodes them back, following the latest MessagePack specification including support for binary, UTF-8 string, and application-defined extension types. The package has no external dependencies and runs on CPython and PyPy across Python 2 and Python 3.

It is typically used when you need a lightweight, portable serialization mechanism for inter-process communication, network protocols, or data storage where MessagePack's compact format is preferable to JSON or pickle. Because it is written entirely in Python, it trades some performance for simplicity and ease of deployment—no compilation or system libraries required.

Use it for:

- Serialize structured data for transmission over network sockets or message queues
- Store application state or configuration in a compact binary format
- Implement RPC or microservice communication protocols using MessagePack as the wire format
- Exchange data between Python and other languages that support MessagePack
- Embed serialization in pure-Python environments where C extensions cannot be used

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

u-msgpack-python serializes and deserializes data in MessagePack format, a compact binary protocol compatible with Python 2, Python 3, CPython, and PyPy.

Yes. The package is stable, actively maintained, has zero known vulnerabilities, and installs with no dependencies. It is a solid choice for MessagePack serialization in pure-Python contexts. The main trade-off is performance versus convenience—if you need maximum speed, a C-based implementation may be preferable, but for most applications the pure-Python approach is sufficient and simpler to deploy.

## Install

pip install u-msgpack-python
uv add u-msgpack-python
poetry add u-msgpack-python

## Installing u-msgpack-python

Before you install: Low install friction with no runtime dependencies. The package is actively maintained as of 2026-07-08 and marked Production/Stable, though the latest release dates to 2023-05-18.

License in practice: MIT license permits commercial and private use with minimal restrictions; you may use, modify, and distribute the package freely provided you retain the license notice.

Quickstart:

pip install u-msgpack-python

import u_msgpack

data = {"key": "value"}
packed = u_msgpack.packb(data)
unpacked = u_msgpack.unpackb(packed)

Verify before relying:

- Whether Python 2 support remains practically useful given its end-of-life status
- Performance characteristics compared to other msgpack implementations in production workloads
- Specific use cases where the pure-Python implementation is preferred over C-based alternatives

## Package facts

- License: MIT (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: active
- Downloads: 1.8M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

msgpack serialization python, binary message serializer, lightweight data serialization, msgpack deserializer, compact binary protocol, cross-python serialization, pure python msgpack, serialization, msgpack, pure-python

[View on SkillFed](https://skillfed.io/packages/u-msgpack-python) · [View on PyPI](https://pypi.org/project/u-msgpack-python/)