ormsgpack

Fast, correct Python msgpack library supporting dataclasses, datetimes, and numpy

ormsgpack Permissive license Apache-2.0 OR MIT Active ★ 400 v1.12.2 released 2026-01-18

Install

ormsgpack on PyPI

pip

pip install ormsgpack

uv

uv add ormsgpack

poetry

poetry add ormsgpack

Package facts

License	Apache-2.0 OR MIT (permissive)
Python support	supports the current Python release (>=3.10)
Install friction	medium — platform-specific wheel
Runtime dependencies	none
Maintenance	actively maintained — 207 days since the last release
Last repo commit	2026-08-07
First released	2021-06-08
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: ormsgpack-1.12.2-cp310-cp310-macosx_10_12_x86_64.macosx_11_0_arm64.macosx_10_12_universal2.whl; ormsgpack-1.12.2-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; ormsgpack-1.12.2-cp310-cp310-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; ormsgpack-1.12.2-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl; ormsgpack-1.12.2-cp310-cp310-musllinux_1_2_aarch64.whl; ormsgpack-1.12.2-cp310-cp310-musllinux_1_2_armv7l.whl; ormsgpack-1.12.2-cp310-cp310-musllinux_1_2_x86_64.whl; ormsgpack-1.12.2-cp310-cp310-win_amd64.whl; ormsgpack-1.12.2-cp311-cp311-macosx_10_12_x86_64.macosx_11_0_arm64.macosx_10_12_universal2.whl; ormsgpack-1.12.2-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; ormsgpack-1.12.2-cp311-cp311-manylinux_2_17_armv7l.manylinux2014_armv7l.whl; ormsgpack-1.12.2-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl; ormsgpack-1.12.2-cp311-cp311-musllinux_1_2_aarch64.whl; ormsgpack-1.12.2-cp311-cp311-musllinux_1_2_armv7l.whl; ormsgpack-1.12.2-cp311-cp311-musllinux_1_2_x86_64.whl; ormsgpack-1.12.2-cp311-cp311-win_amd64.whl; ormsgpack-1.12.2-cp311-cp311-win_arm64.whl; ormsgpack-1.12.2-cp312-cp312-macosx_10_12_x86_64.macosx_11_0_arm64.macosx_10_12_universal2.whl; ormsgpack-1.12.2-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl; ormsgpack-1.12.2-cp312-cp312-manylinux_2_17_armv7l.manylinux2014_armv7l.whl

Keywords: fast, msgpack, dataclass, dataclasses, datetime

Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: Apache Software LicenseLicense :: OSI Approved :: MIT LicenseOperating System :: MacOSOperating System :: Microsoft :: WindowsOperating System :: POSIX :: LinuxProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: GraalPyProgramming Language :: Python :: Implementation :: PyPyProgramming Language :: RustTyping :: Typed

About ormsgpack

from the package's own PyPI description — quoted content, verbatim

ormsgpack

PyPI - Version (image) PyPI - Python Version (image) PyPI - Downloads (image)

ormsgpack is a fast MessagePack serialization library for Python derived from orjson, with native support for various Python types.

ormsgpack follows semantic versioning and supports CPython, PyPy and GraalPy.

Links:

Installation

pip

pip install ormsgpack

uv add ormsgpack

Installing from a source distribution requires Rust 1.81 or newer and maturin.

Quickstart

This is an example of serializing and deserializing an object:

```python >>> import ormsgpack, datetime, numpy >>> event = { ... "type": "put", ... "time": datetime.datetime(1970, 1, 1), ... "uid": 1, ... "data": numpy.array([1, 2]), ... } >>> ormsgpack.packb(event,...

Read as markdown · JSON record · Source repository · Homepage

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

ormsgpack is a fast MessagePack serialization library for Python with native support for dataclasses, datetimes, and numpy arrays, derived from orjson.

Medium install friction due to compiled Rust bindings, but pre-built wheels cover Python 3.10–3.14 across macOS, Linux, Windows, and ARM platforms. Active maintenance with recent releases and no known vulnerabilities.

Dual-licensed under Apache-2.0 or MIT (permissive), allowing use in most commercial and open-source projects without restriction.

Usage

import ormsgpack
import datetime

event = {"type": "put", "time": datetime.datetime(1970, 1, 1)}
packed = ormsgpack.packb(event)
unpacked = ormsgpack.unpackb(packed)

Requires Python ≥3.10; installing from source requires Rust 1.81+ and maturin.

Verdict: ormsgpack is a production-ready, actively maintained serialization library with broad platform coverage and no security issues. Medium install friction is offset by pre-built wheels for all major Python versions and platforms, making it suitable for performance-critical applications needing fast MessagePack encoding with rich type support.

Needs verification

Performance benchmarks vs. standard msgpack or other serializers to validate 'fast' claim
Whether numpy support requires numpy as an optional dependency or is built-in

msgpack serialization pythonfast binary serializationmessagepack encoder decoderdataclass serializationnumpy array serializationdatetime msgpackhigh performance msgpack