librt

Mypyc runtime library

librt Permissive license MIT Active ★ 14 v0.15.0 released 2026-08-07

Install

librt on PyPI

pip

pip install librt

uv

uv add librt

poetry

poetry add librt

Package facts

License	MIT (permissive)
Python support	supports the current Python release (>=3.9)
Install friction	medium — platform-specific wheel
Runtime dependencies	none
Maintenance	actively maintained — 6 days since the last release
Last repo commit	2026-08-07
First released	2025-09-14
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: librt-0.15.0-cp310-cp310-macosx_10_9_x86_64.whl; librt-0.15.0-cp310-cp310-macosx_11_0_arm64.whl; librt-0.15.0-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; librt-0.15.0-cp310-cp310-manylinux2014_i686.manylinux_2_17_i686.manylinux_2_28_i686.whl; librt-0.15.0-cp310-cp310-manylinux2014_ppc64le.manylinux_2_17_ppc64le.manylinux_2_28_ppc64le.whl; librt-0.15.0-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; librt-0.15.0-cp310-cp310-manylinux_2_34_riscv64.manylinux_2_39_riscv64.whl; librt-0.15.0-cp310-cp310-musllinux_1_2_aarch64.whl; librt-0.15.0-cp310-cp310-musllinux_1_2_i686.whl; librt-0.15.0-cp310-cp310-musllinux_1_2_ppc64le.whl; librt-0.15.0-cp310-cp310-musllinux_1_2_riscv64.whl; librt-0.15.0-cp310-cp310-musllinux_1_2_x86_64.whl; librt-0.15.0-cp310-cp310-win32.whl; librt-0.15.0-cp310-cp310-win_amd64.whl; librt-0.15.0-cp311-cp311-macosx_10_9_x86_64.whl; librt-0.15.0-cp311-cp311-macosx_11_0_arm64.whl; librt-0.15.0-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; librt-0.15.0-cp311-cp311-manylinux2014_i686.manylinux_2_17_i686.manylinux_2_28_i686.whl; librt-0.15.0-cp311-cp311-manylinux2014_ppc64le.manylinux_2_17_ppc64le.manylinux_2_28_ppc64le.whl; librt-0.15.0-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl

Development Status :: 3 - AlphaEnvironment :: ConsoleIntended Audience :: DevelopersProgramming 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 :: 3.9Topic :: Software DevelopmentTyping :: Typed

About librt

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

librt: mypyc runtime library

Stable Version (image) Downloads (image) Build Status (image) Checked with mypy (image)

This library contains basic functionality that is useful in code compiled using the mypyc compiler, and efficient C alternatives to various Python standard library classes and functions. Mypyc can produce faster extensions when you use librt in the code you compile. librt also contains some internal library features used by mypy.

Here are some feature highlights:

librt.vecs defines the growable packed array-like type vec
librt.strings defines fast string and bytes builders and binary data read/write helpers *...

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

librt provides optimized C implementations of runtime utilities for code compiled with mypyc, including growable arrays, fast string/bytes builders, and SIMD-accelerated Base64 encoding.

Medium install friction due to platform-specific wheels across many architectures (x86_64, ARM, RISC-V, PowerPC, i686, Windows, macOS, Linux, musl). Active maintenance with a release 6 days ago; however, PyPy is explicitly unsupported.

MIT license permits commercial and private use with minimal restrictions, making it suitable for most projects.

Usage

pip install librt==0.15.0

from librt.vecs import vec
from librt.strings import Builder

Requires Python 3.9 or later; PyPy is not supported. Pre-built wheels exist for CPython 3.10–3.14 on multiple platforms, but source installation requires manual directory setup per developer notes.

Verdict: librt is an actively maintained, permissively licensed runtime library for mypyc-compiled code with no known vulnerabilities. Its medium install friction stems from extensive platform-specific wheels rather than dependency complexity. Suitable for projects using mypyc or mypy, though PyPy users should note explicit non-support.

Needs verification

Whether pre-built wheels for Python 3.9 exist (classifiers list 3.9 support but friction evidence shows only 3.10+)
Performance gains from using librt in compiled code compared to standard Python equivalents
Whether librt is required or optional for mypyc projects

mypyc runtime libraryfast string builders pythongrowable array vec typesimd base64 encodingmypyc compiled code utilities